Actual source code: matrix.c

  1: /*
  2:    This is where the abstract matrix operations are defined
  3:    Portions of this code are under:
  4:    Copyright (c) 2022 Advanced Micro Devices, Inc. All rights reserved.
  5: */

  7: #include <petsc/private/matimpl.h>
  8: #include <petsc/private/isimpl.h>
  9: #include <petsc/private/vecimpl.h>

 11: /* Logging support */
 12: PetscClassId MAT_CLASSID;
 13: PetscClassId MAT_COLORING_CLASSID;
 14: PetscClassId MAT_FDCOLORING_CLASSID;
 15: PetscClassId MAT_TRANSPOSECOLORING_CLASSID;

 17: PetscLogEvent MAT_Mult, MAT_MultAdd, MAT_MultTranspose;
 18: PetscLogEvent MAT_MultTransposeAdd, MAT_Solve, MAT_Solves, MAT_SolveAdd, MAT_SolveTranspose, MAT_MatSolve, MAT_MatTrSolve;
 19: PetscLogEvent MAT_SolveTransposeAdd, MAT_SOR, MAT_ForwardSolve, MAT_BackwardSolve, MAT_LUFactor, MAT_LUFactorSymbolic;
 20: PetscLogEvent MAT_LUFactorNumeric, MAT_CholeskyFactor, MAT_CholeskyFactorSymbolic, MAT_CholeskyFactorNumeric, MAT_ILUFactor;
 21: PetscLogEvent MAT_ILUFactorSymbolic, MAT_ICCFactorSymbolic, MAT_Copy, MAT_Convert, MAT_Scale, MAT_AssemblyBegin;
 22: PetscLogEvent MAT_QRFactorNumeric, MAT_QRFactorSymbolic, MAT_QRFactor;
 23: PetscLogEvent MAT_AssemblyEnd, MAT_SetValues, MAT_GetValues, MAT_GetRow, MAT_GetRowIJ, MAT_CreateSubMats, MAT_GetOrdering, MAT_RedundantMat, MAT_GetSeqNonzeroStructure;
 24: PetscLogEvent MAT_IncreaseOverlap, MAT_Partitioning, MAT_PartitioningND, MAT_Coarsen, MAT_ZeroEntries, MAT_Load, MAT_View, MAT_AXPY, MAT_FDColoringCreate;
 25: PetscLogEvent MAT_FDColoringSetUp, MAT_FDColoringApply, MAT_Transpose, MAT_FDColoringFunction, MAT_CreateSubMat;
 26: PetscLogEvent MAT_TransposeColoringCreate;
 27: PetscLogEvent MAT_MatMult, MAT_MatMultSymbolic, MAT_MatMultNumeric;
 28: PetscLogEvent MAT_PtAP, MAT_PtAPSymbolic, MAT_PtAPNumeric, MAT_RARt, MAT_RARtSymbolic, MAT_RARtNumeric;
 29: PetscLogEvent MAT_MatTransposeMult, MAT_MatTransposeMultSymbolic, MAT_MatTransposeMultNumeric;
 30: PetscLogEvent MAT_TransposeMatMult, MAT_TransposeMatMultSymbolic, MAT_TransposeMatMultNumeric;
 31: PetscLogEvent MAT_MatMatMult, MAT_MatMatMultSymbolic, MAT_MatMatMultNumeric;
 32: PetscLogEvent MAT_MultHermitianTranspose, MAT_MultHermitianTransposeAdd;
 33: PetscLogEvent MAT_Getsymtransreduced, MAT_GetBrowsOfAcols;
 34: PetscLogEvent MAT_GetBrowsOfAocols, MAT_Getlocalmat, MAT_Getlocalmatcondensed, MAT_Seqstompi, MAT_Seqstompinum, MAT_Seqstompisym;
 35: PetscLogEvent MAT_GetMultiProcBlock;
 36: PetscLogEvent MAT_CUSPARSECopyToGPU, MAT_CUSPARSECopyFromGPU, MAT_CUSPARSEGenerateTranspose, MAT_CUSPARSESolveAnalysis;
 37: PetscLogEvent MAT_HIPSPARSECopyToGPU, MAT_HIPSPARSECopyFromGPU, MAT_HIPSPARSEGenerateTranspose, MAT_HIPSPARSESolveAnalysis;
 38: PetscLogEvent MAT_PreallCOO, MAT_SetVCOO;
 39: PetscLogEvent MAT_CreateGraph;
 40: PetscLogEvent MAT_SetValuesBatch;
 41: PetscLogEvent MAT_ViennaCLCopyToGPU;
 42: PetscLogEvent MAT_CUDACopyToGPU, MAT_HIPCopyToGPU;
 43: PetscLogEvent MAT_DenseCopyToGPU, MAT_DenseCopyFromGPU;
 44: PetscLogEvent MAT_Merge, MAT_Residual, MAT_SetRandom;
 45: PetscLogEvent MAT_FactorFactS, MAT_FactorInvS;
 46: PetscLogEvent MATCOLORING_Apply, MATCOLORING_Comm, MATCOLORING_Local, MATCOLORING_ISCreate, MATCOLORING_SetUp, MATCOLORING_Weights;
 47: PetscLogEvent MAT_H2Opus_Build, MAT_H2Opus_Compress, MAT_H2Opus_Orthog, MAT_H2Opus_LR;

 49: const char *const MatFactorTypes[] = {"NONE", "LU", "CHOLESKY", "ILU", "ICC", "ILUDT", "QR", "MatFactorType", "MAT_FACTOR_", NULL};

 51: /*@
 52:   MatSetRandom - Sets all components of a matrix to random numbers.

 54:   Logically Collective

 56:   Input Parameters:
 57: + x    - the matrix
 58: - rctx - the `PetscRandom` object, formed by `PetscRandomCreate()`, or `NULL` and
 59:           it will create one internally.

 61:   Example:
 62: .vb
 63:      PetscRandomCreate(PETSC_COMM_WORLD,&rctx);
 64:      MatSetRandom(x,rctx);
 65:      PetscRandomDestroy(rctx);
 66: .ve

 68:   Level: intermediate

 70:   Notes:
 71:   For sparse matrices that have been preallocated but not been assembled, it randomly selects appropriate locations,

 73:   for sparse matrices that already have nonzero locations, it fills the locations with random numbers.

 75:   It generates an error if used on unassembled sparse matrices that have not been preallocated.

 77: .seealso: [](ch_matrices), `Mat`, `PetscRandom`, `PetscRandomCreate()`, `MatZeroEntries()`, `MatSetValues()`, `PetscRandomDestroy()`
 78: @*/
 79: PetscErrorCode MatSetRandom(Mat x, PetscRandom rctx)
 80: {
 81:   PetscRandom randObj = NULL;

 83:   PetscFunctionBegin;
 87:   MatCheckPreallocated(x, 1);

 89:   if (!rctx) {
 90:     MPI_Comm comm;
 91:     PetscCall(PetscObjectGetComm((PetscObject)x, &comm));
 92:     PetscCall(PetscRandomCreate(comm, &randObj));
 93:     PetscCall(PetscRandomSetType(randObj, x->defaultrandtype));
 94:     PetscCall(PetscRandomSetFromOptions(randObj));
 95:     rctx = randObj;
 96:   }
 97:   PetscCall(PetscLogEventBegin(MAT_SetRandom, x, rctx, 0, 0));
 98:   PetscUseTypeMethod(x, setrandom, rctx);
 99:   PetscCall(PetscLogEventEnd(MAT_SetRandom, x, rctx, 0, 0));

101:   PetscCall(MatAssemblyBegin(x, MAT_FINAL_ASSEMBLY));
102:   PetscCall(MatAssemblyEnd(x, MAT_FINAL_ASSEMBLY));
103:   PetscCall(PetscRandomDestroy(&randObj));
104:   PetscFunctionReturn(PETSC_SUCCESS);
105: }

107: /*@
108:   MatFactorGetErrorZeroPivot - returns the pivot value that was determined to be zero and the row it occurred in

110:   Logically Collective

112:   Input Parameter:
113: . mat - the factored matrix

115:   Output Parameters:
116: + pivot - the pivot value computed
117: - row   - the row that the zero pivot occurred. This row value must be interpreted carefully due to row reorderings and which processes
118:          the share the matrix

120:   Level: advanced

122:   Notes:
123:   This routine does not work for factorizations done with external packages.

125:   This routine should only be called if `MatGetFactorError()` returns a value of `MAT_FACTOR_NUMERIC_ZEROPIVOT`

127:   This can also be called on non-factored matrices that come from, for example, matrices used in SOR.

129: .seealso: [](ch_matrices), `Mat`, `MatZeroEntries()`, `MatFactor()`, `MatGetFactor()`,
130: `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`, `MatFactorClearError()`,
131: `MAT_FACTOR_NUMERIC_ZEROPIVOT`
132: @*/
133: PetscErrorCode MatFactorGetErrorZeroPivot(Mat mat, PetscReal *pivot, PetscInt *row)
134: {
135:   PetscFunctionBegin;
137:   PetscAssertPointer(pivot, 2);
138:   PetscAssertPointer(row, 3);
139:   *pivot = mat->factorerror_zeropivot_value;
140:   *row   = mat->factorerror_zeropivot_row;
141:   PetscFunctionReturn(PETSC_SUCCESS);
142: }

144: /*@
145:   MatFactorGetError - gets the error code from a factorization

147:   Logically Collective

149:   Input Parameter:
150: . mat - the factored matrix

152:   Output Parameter:
153: . err - the error code

155:   Level: advanced

157:   Note:
158:   This can also be called on non-factored matrices that come from, for example, matrices used in SOR.

160: .seealso: [](ch_matrices), `Mat`, `MatZeroEntries()`, `MatFactor()`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`,
161:           `MatFactorClearError()`, `MatFactorGetErrorZeroPivot()`, `MatFactorError`
162: @*/
163: PetscErrorCode MatFactorGetError(Mat mat, MatFactorError *err)
164: {
165:   PetscFunctionBegin;
167:   PetscAssertPointer(err, 2);
168:   *err = mat->factorerrortype;
169:   PetscFunctionReturn(PETSC_SUCCESS);
170: }

172: /*@
173:   MatFactorClearError - clears the error code in a factorization

175:   Logically Collective

177:   Input Parameter:
178: . mat - the factored matrix

180:   Level: developer

182:   Note:
183:   This can also be called on non-factored matrices that come from, for example, matrices used in SOR.

185: .seealso: [](ch_matrices), `Mat`, `MatZeroEntries()`, `MatFactor()`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`, `MatFactorGetError()`, `MatFactorGetErrorZeroPivot()`,
186:           `MatGetErrorCode()`, `MatFactorError`
187: @*/
188: PetscErrorCode MatFactorClearError(Mat mat)
189: {
190:   PetscFunctionBegin;
192:   mat->factorerrortype             = MAT_FACTOR_NOERROR;
193:   mat->factorerror_zeropivot_value = 0.0;
194:   mat->factorerror_zeropivot_row   = 0;
195:   PetscFunctionReturn(PETSC_SUCCESS);
196: }

198: PetscErrorCode MatFindNonzeroRowsOrCols_Basic(Mat mat, PetscBool cols, PetscReal tol, IS *nonzero)
199: {
200:   Vec                r, l;
201:   const PetscScalar *al;
202:   PetscInt           i, nz, gnz, N, n, st;

204:   PetscFunctionBegin;
205:   PetscCall(MatCreateVecs(mat, &r, &l));
206:   if (!cols) { /* nonzero rows */
207:     PetscCall(MatGetOwnershipRange(mat, &st, NULL));
208:     PetscCall(MatGetSize(mat, &N, NULL));
209:     PetscCall(MatGetLocalSize(mat, &n, NULL));
210:     PetscCall(VecSet(l, 0.0));
211:     PetscCall(VecSetRandom(r, NULL));
212:     PetscCall(MatMult(mat, r, l));
213:     PetscCall(VecGetArrayRead(l, &al));
214:   } else { /* nonzero columns */
215:     PetscCall(MatGetOwnershipRangeColumn(mat, &st, NULL));
216:     PetscCall(MatGetSize(mat, NULL, &N));
217:     PetscCall(MatGetLocalSize(mat, NULL, &n));
218:     PetscCall(VecSet(r, 0.0));
219:     PetscCall(VecSetRandom(l, NULL));
220:     PetscCall(MatMultTranspose(mat, l, r));
221:     PetscCall(VecGetArrayRead(r, &al));
222:   }
223:   if (tol <= 0.0) {
224:     for (i = 0, nz = 0; i < n; i++)
225:       if (al[i] != 0.0) nz++;
226:   } else {
227:     for (i = 0, nz = 0; i < n; i++)
228:       if (PetscAbsScalar(al[i]) > tol) nz++;
229:   }
230:   PetscCallMPI(MPIU_Allreduce(&nz, &gnz, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)mat)));
231:   if (gnz != N) {
232:     PetscInt *nzr;
233:     PetscCall(PetscMalloc1(nz, &nzr));
234:     if (nz) {
235:       if (tol < 0) {
236:         for (i = 0, nz = 0; i < n; i++)
237:           if (al[i] != 0.0) nzr[nz++] = i + st;
238:       } else {
239:         for (i = 0, nz = 0; i < n; i++)
240:           if (PetscAbsScalar(al[i]) > tol) nzr[nz++] = i + st;
241:       }
242:     }
243:     PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)mat), nz, nzr, PETSC_OWN_POINTER, nonzero));
244:   } else *nonzero = NULL;
245:   if (!cols) { /* nonzero rows */
246:     PetscCall(VecRestoreArrayRead(l, &al));
247:   } else {
248:     PetscCall(VecRestoreArrayRead(r, &al));
249:   }
250:   PetscCall(VecDestroy(&l));
251:   PetscCall(VecDestroy(&r));
252:   PetscFunctionReturn(PETSC_SUCCESS);
253: }

255: /*@
256:   MatFindNonzeroRows - Locate all rows that are not completely zero in the matrix

258:   Input Parameter:
259: . mat - the matrix

261:   Output Parameter:
262: . keptrows - the rows that are not completely zero

264:   Level: intermediate

266:   Note:
267:   `keptrows` is set to `NULL` if all rows are nonzero.

269:   Developer Note:
270:   If `keptrows` is not `NULL`, it must be sorted.

272: .seealso: [](ch_matrices), `Mat`, `MatFindZeroRows()`
273:  @*/
274: PetscErrorCode MatFindNonzeroRows(Mat mat, IS *keptrows)
275: {
276:   PetscFunctionBegin;
279:   PetscAssertPointer(keptrows, 2);
280:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
281:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
282:   if (mat->ops->findnonzerorows) PetscUseTypeMethod(mat, findnonzerorows, keptrows);
283:   else PetscCall(MatFindNonzeroRowsOrCols_Basic(mat, PETSC_FALSE, 0.0, keptrows));
284:   if (keptrows && *keptrows) PetscCall(ISSetInfo(*keptrows, IS_SORTED, IS_GLOBAL, PETSC_FALSE, PETSC_TRUE));
285:   PetscFunctionReturn(PETSC_SUCCESS);
286: }

288: /*@
289:   MatFindZeroRows - Locate all rows that are completely zero in the matrix

291:   Input Parameter:
292: . mat - the matrix

294:   Output Parameter:
295: . zerorows - the rows that are completely zero

297:   Level: intermediate

299:   Note:
300:   `zerorows` is set to `NULL` if no rows are zero.

302: .seealso: [](ch_matrices), `Mat`, `MatFindNonzeroRows()`
303:  @*/
304: PetscErrorCode MatFindZeroRows(Mat mat, IS *zerorows)
305: {
306:   IS       keptrows;
307:   PetscInt m, n;

309:   PetscFunctionBegin;
312:   PetscAssertPointer(zerorows, 2);
313:   PetscCall(MatFindNonzeroRows(mat, &keptrows));
314:   /* MatFindNonzeroRows sets keptrows to NULL if there are no zero rows.
315:      In keeping with this convention, we set zerorows to NULL if there are no zero
316:      rows. */
317:   if (keptrows == NULL) {
318:     *zerorows = NULL;
319:   } else {
320:     PetscCall(MatGetOwnershipRange(mat, &m, &n));
321:     PetscCall(ISComplement(keptrows, m, n, zerorows));
322:     PetscCall(ISDestroy(&keptrows));
323:   }
324:   PetscFunctionReturn(PETSC_SUCCESS);
325: }

327: /*@
328:   MatGetDiagonalBlock - Returns the part of the matrix associated with the on-process coupling

330:   Not Collective

332:   Input Parameter:
333: . A - the matrix

335:   Output Parameter:
336: . a - the diagonal part (which is a SEQUENTIAL matrix)

338:   Level: advanced

340:   Notes:
341:   See `MatCreateAIJ()` for more information on the "diagonal part" of the matrix.

343:   Use caution, as the reference count on the returned matrix is not incremented and it is used as part of `A`'s normal operation.

345: .seealso: [](ch_matrices), `Mat`, `MatCreateAIJ()`, `MATAIJ`, `MATBAIJ`, `MATSBAIJ`
346: @*/
347: PetscErrorCode MatGetDiagonalBlock(Mat A, Mat *a)
348: {
349:   PetscFunctionBegin;
352:   PetscAssertPointer(a, 2);
353:   PetscCheck(!A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
354:   if (A->ops->getdiagonalblock) PetscUseTypeMethod(A, getdiagonalblock, a);
355:   else {
356:     PetscMPIInt size;

358:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size));
359:     PetscCheck(size == 1, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Not for parallel matrix type %s", ((PetscObject)A)->type_name);
360:     *a = A;
361:   }
362:   PetscFunctionReturn(PETSC_SUCCESS);
363: }

365: /*@
366:   MatGetTrace - Gets the trace of a matrix. The sum of the diagonal entries.

368:   Collective

370:   Input Parameter:
371: . mat - the matrix

373:   Output Parameter:
374: . trace - the sum of the diagonal entries

376:   Level: advanced

378: .seealso: [](ch_matrices), `Mat`
379: @*/
380: PetscErrorCode MatGetTrace(Mat mat, PetscScalar *trace)
381: {
382:   Vec diag;

384:   PetscFunctionBegin;
386:   PetscAssertPointer(trace, 2);
387:   PetscCall(MatCreateVecs(mat, &diag, NULL));
388:   PetscCall(MatGetDiagonal(mat, diag));
389:   PetscCall(VecSum(diag, trace));
390:   PetscCall(VecDestroy(&diag));
391:   PetscFunctionReturn(PETSC_SUCCESS);
392: }

394: /*@
395:   MatRealPart - Zeros out the imaginary part of the matrix

397:   Logically Collective

399:   Input Parameter:
400: . mat - the matrix

402:   Level: advanced

404: .seealso: [](ch_matrices), `Mat`, `MatImaginaryPart()`
405: @*/
406: PetscErrorCode MatRealPart(Mat mat)
407: {
408:   PetscFunctionBegin;
411:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
412:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
413:   MatCheckPreallocated(mat, 1);
414:   PetscUseTypeMethod(mat, realpart);
415:   PetscFunctionReturn(PETSC_SUCCESS);
416: }

418: /*@C
419:   MatGetGhosts - Get the global indices of all ghost nodes defined by the sparse matrix

421:   Collective

423:   Input Parameter:
424: . mat - the matrix

426:   Output Parameters:
427: + nghosts - number of ghosts (for `MATBAIJ` and `MATSBAIJ` matrices there is one ghost for each matrix block)
428: - ghosts  - the global indices of the ghost points

430:   Level: advanced

432:   Note:
433:   `nghosts` and `ghosts` are suitable to pass into `VecCreateGhost()` or `VecCreateGhostBlock()`

435: .seealso: [](ch_matrices), `Mat`, `VecCreateGhost()`, `VecCreateGhostBlock()`
436: @*/
437: PetscErrorCode MatGetGhosts(Mat mat, PetscInt *nghosts, const PetscInt *ghosts[])
438: {
439:   PetscFunctionBegin;
442:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
443:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
444:   if (mat->ops->getghosts) PetscUseTypeMethod(mat, getghosts, nghosts, ghosts);
445:   else {
446:     if (nghosts) *nghosts = 0;
447:     if (ghosts) *ghosts = NULL;
448:   }
449:   PetscFunctionReturn(PETSC_SUCCESS);
450: }

452: /*@
453:   MatImaginaryPart - Moves the imaginary part of the matrix to the real part and zeros the imaginary part

455:   Logically Collective

457:   Input Parameter:
458: . mat - the matrix

460:   Level: advanced

462: .seealso: [](ch_matrices), `Mat`, `MatRealPart()`
463: @*/
464: PetscErrorCode MatImaginaryPart(Mat mat)
465: {
466:   PetscFunctionBegin;
469:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
470:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
471:   MatCheckPreallocated(mat, 1);
472:   PetscUseTypeMethod(mat, imaginarypart);
473:   PetscFunctionReturn(PETSC_SUCCESS);
474: }

476: /*@
477:   MatMissingDiagonal - Determine if sparse matrix is missing a diagonal entry (or block entry for `MATBAIJ` and `MATSBAIJ` matrices) in the nonzero structure

479:   Not Collective

481:   Input Parameter:
482: . mat - the matrix

484:   Output Parameters:
485: + missing - is any diagonal entry missing
486: - dd      - first diagonal entry that is missing (optional) on this process

488:   Level: advanced

490:   Note:
491:   This does not return diagonal entries that are in the nonzero structure but happen to have a zero numerical value

493: .seealso: [](ch_matrices), `Mat`
494: @*/
495: PetscErrorCode MatMissingDiagonal(Mat mat, PetscBool *missing, PetscInt *dd)
496: {
497:   PetscFunctionBegin;
500:   PetscAssertPointer(missing, 2);
501:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix %s", ((PetscObject)mat)->type_name);
502:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
503:   PetscUseTypeMethod(mat, missingdiagonal, missing, dd);
504:   PetscFunctionReturn(PETSC_SUCCESS);
505: }

507: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
508: /*@C
509:   MatGetRow - Gets a row of a matrix.  You MUST call `MatRestoreRow()`
510:   for each row that you get to ensure that your application does
511:   not bleed memory.

513:   Not Collective

515:   Input Parameters:
516: + mat - the matrix
517: - row - the row to get

519:   Output Parameters:
520: + ncols - if not `NULL`, the number of nonzeros in `row`
521: . cols  - if not `NULL`, the column numbers
522: - vals  - if not `NULL`, the numerical values

524:   Level: advanced

526:   Notes:
527:   This routine is provided for people who need to have direct access
528:   to the structure of a matrix.  We hope that we provide enough
529:   high-level matrix routines that few users will need it.

531:   `MatGetRow()` always returns 0-based column indices, regardless of
532:   whether the internal representation is 0-based (default) or 1-based.

534:   For better efficiency, set `cols` and/or `vals` to `NULL` if you do
535:   not wish to extract these quantities.

537:   The user can only examine the values extracted with `MatGetRow()`;
538:   the values CANNOT be altered.  To change the matrix entries, one
539:   must use `MatSetValues()`.

541:   You can only have one call to `MatGetRow()` outstanding for a particular
542:   matrix at a time, per processor. `MatGetRow()` can only obtain rows
543:   associated with the given processor, it cannot get rows from the
544:   other processors; for that we suggest using `MatCreateSubMatrices()`, then
545:   `MatGetRow()` on the submatrix. The row index passed to `MatGetRow()`
546:   is in the global number of rows.

548:   Use `MatGetRowIJ()` and `MatRestoreRowIJ()` to access all the local indices of the sparse matrix.

550:   Use `MatSeqAIJGetArray()` and similar functions to access the numerical values for certain matrix types directly.

552:   Fortran Note:
553:   The calling sequence is
554: .vb
555:    MatGetRow(matrix,row,ncols,cols,values,ierr)
556:          Mat         matrix (input)
557:          PetscInt    row    (input)
558:          PetscInt    ncols  (output)
559:          PetscInt    cols(maxcols) (output)
560:          PetscScalar values(maxcols) output
561: .ve
562:   where maxcols >= maximum nonzeros in any row of the matrix.

564: .seealso: [](ch_matrices), `Mat`, `MatRestoreRow()`, `MatSetValues()`, `MatGetValues()`, `MatCreateSubMatrices()`, `MatGetDiagonal()`, `MatGetRowIJ()`, `MatRestoreRowIJ()`
565: @*/
566: PetscErrorCode MatGetRow(Mat mat, PetscInt row, PetscInt *ncols, const PetscInt *cols[], const PetscScalar *vals[])
567: {
568:   PetscInt incols;

570:   PetscFunctionBegin;
573:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
574:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
575:   MatCheckPreallocated(mat, 1);
576:   PetscCheck(row >= mat->rmap->rstart && row < mat->rmap->rend, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Only for local rows, %" PetscInt_FMT " not in [%" PetscInt_FMT ",%" PetscInt_FMT ")", row, mat->rmap->rstart, mat->rmap->rend);
577:   PetscCall(PetscLogEventBegin(MAT_GetRow, mat, 0, 0, 0));
578:   PetscUseTypeMethod(mat, getrow, row, &incols, (PetscInt **)cols, (PetscScalar **)vals);
579:   if (ncols) *ncols = incols;
580:   PetscCall(PetscLogEventEnd(MAT_GetRow, mat, 0, 0, 0));
581:   PetscFunctionReturn(PETSC_SUCCESS);
582: }

584: /*@
585:   MatConjugate - replaces the matrix values with their complex conjugates

587:   Logically Collective

589:   Input Parameter:
590: . mat - the matrix

592:   Level: advanced

594: .seealso: [](ch_matrices), `Mat`, `MatRealPart()`, `MatImaginaryPart()`, `VecConjugate()`, `MatTranspose()`
595: @*/
596: PetscErrorCode MatConjugate(Mat mat)
597: {
598:   PetscFunctionBegin;
600:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
601:   if (PetscDefined(USE_COMPLEX) && mat->hermitian != PETSC_BOOL3_TRUE) {
602:     PetscUseTypeMethod(mat, conjugate);
603:     PetscCall(PetscObjectStateIncrease((PetscObject)mat));
604:   }
605:   PetscFunctionReturn(PETSC_SUCCESS);
606: }

608: /*@C
609:   MatRestoreRow - Frees any temporary space allocated by `MatGetRow()`.

611:   Not Collective

613:   Input Parameters:
614: + mat   - the matrix
615: . row   - the row to get
616: . ncols - the number of nonzeros
617: . cols  - the columns of the nonzeros
618: - vals  - if nonzero the column values

620:   Level: advanced

622:   Notes:
623:   This routine should be called after you have finished examining the entries.

625:   This routine zeros out `ncols`, `cols`, and `vals`. This is to prevent accidental
626:   us of the array after it has been restored. If you pass `NULL`, it will
627:   not zero the pointers.  Use of `cols` or `vals` after `MatRestoreRow()` is invalid.

629:   Fortran Note:
630:   `MatRestoreRow()` MUST be called after `MatGetRow()`
631:   before another call to `MatGetRow()` can be made.

633: .seealso: [](ch_matrices), `Mat`, `MatGetRow()`
634: @*/
635: PetscErrorCode MatRestoreRow(Mat mat, PetscInt row, PetscInt *ncols, const PetscInt *cols[], const PetscScalar *vals[])
636: {
637:   PetscFunctionBegin;
639:   if (ncols) PetscAssertPointer(ncols, 3);
640:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
641:   if (!mat->ops->restorerow) PetscFunctionReturn(PETSC_SUCCESS);
642:   PetscUseTypeMethod(mat, restorerow, row, ncols, (PetscInt **)cols, (PetscScalar **)vals);
643:   if (ncols) *ncols = 0;
644:   if (cols) *cols = NULL;
645:   if (vals) *vals = NULL;
646:   PetscFunctionReturn(PETSC_SUCCESS);
647: }

649: /*@
650:   MatGetRowUpperTriangular - Sets a flag to enable calls to `MatGetRow()` for matrix in `MATSBAIJ` format.
651:   You should call `MatRestoreRowUpperTriangular()` after calling` MatGetRow()` and `MatRestoreRow()` to disable the flag.

653:   Not Collective

655:   Input Parameter:
656: . mat - the matrix

658:   Level: advanced

660:   Note:
661:   The flag is to ensure that users are aware that `MatGetRow()` only provides the upper triangular part of the row for the matrices in `MATSBAIJ` format.

663: .seealso: [](ch_matrices), `Mat`, `MATSBAIJ`, `MatRestoreRowUpperTriangular()`
664: @*/
665: PetscErrorCode MatGetRowUpperTriangular(Mat mat)
666: {
667:   PetscFunctionBegin;
670:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
671:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
672:   MatCheckPreallocated(mat, 1);
673:   if (!mat->ops->getrowuppertriangular) PetscFunctionReturn(PETSC_SUCCESS);
674:   PetscUseTypeMethod(mat, getrowuppertriangular);
675:   PetscFunctionReturn(PETSC_SUCCESS);
676: }

678: /*@
679:   MatRestoreRowUpperTriangular - Disable calls to `MatGetRow()` for matrix in `MATSBAIJ` format.

681:   Not Collective

683:   Input Parameter:
684: . mat - the matrix

686:   Level: advanced

688:   Note:
689:   This routine should be called after you have finished calls to `MatGetRow()` and `MatRestoreRow()`.

691: .seealso: [](ch_matrices), `Mat`, `MATSBAIJ`, `MatGetRowUpperTriangular()`
692: @*/
693: PetscErrorCode MatRestoreRowUpperTriangular(Mat mat)
694: {
695:   PetscFunctionBegin;
698:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
699:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
700:   MatCheckPreallocated(mat, 1);
701:   if (!mat->ops->restorerowuppertriangular) PetscFunctionReturn(PETSC_SUCCESS);
702:   PetscUseTypeMethod(mat, restorerowuppertriangular);
703:   PetscFunctionReturn(PETSC_SUCCESS);
704: }

706: /*@
707:   MatSetOptionsPrefix - Sets the prefix used for searching for all
708:   `Mat` options in the database.

710:   Logically Collective

712:   Input Parameters:
713: + A      - the matrix
714: - prefix - the prefix to prepend to all option names

716:   Level: advanced

718:   Notes:
719:   A hyphen (-) must NOT be given at the beginning of the prefix name.
720:   The first character of all runtime options is AUTOMATICALLY the hyphen.

722:   This is NOT used for options for the factorization of the matrix. Normally the
723:   prefix is automatically passed in from the PC calling the factorization. To set
724:   it directly use  `MatSetOptionsPrefixFactor()`

726: .seealso: [](ch_matrices), `Mat`, `MatSetFromOptions()`, `MatSetOptionsPrefixFactor()`
727: @*/
728: PetscErrorCode MatSetOptionsPrefix(Mat A, const char prefix[])
729: {
730:   PetscFunctionBegin;
732:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)A, prefix));
733:   PetscFunctionReturn(PETSC_SUCCESS);
734: }

736: /*@
737:   MatSetOptionsPrefixFactor - Sets the prefix used for searching for all matrix factor options in the database for
738:   for matrices created with `MatGetFactor()`

740:   Logically Collective

742:   Input Parameters:
743: + A      - the matrix
744: - prefix - the prefix to prepend to all option names for the factored matrix

746:   Level: developer

748:   Notes:
749:   A hyphen (-) must NOT be given at the beginning of the prefix name.
750:   The first character of all runtime options is AUTOMATICALLY the hyphen.

752:   Normally the prefix is automatically passed in from the `PC` calling the factorization. To set
753:   it directly when not using `KSP`/`PC` use  `MatSetOptionsPrefixFactor()`

755: .seealso: [](ch_matrices), `Mat`,   [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatSetFromOptions()`, `MatSetOptionsPrefix()`, `MatAppendOptionsPrefixFactor()`
756: @*/
757: PetscErrorCode MatSetOptionsPrefixFactor(Mat A, const char prefix[])
758: {
759:   PetscFunctionBegin;
761:   if (prefix) {
762:     PetscAssertPointer(prefix, 2);
763:     PetscCheck(prefix[0] != '-', PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Options prefix should not begin with a hyphen");
764:     if (prefix != A->factorprefix) {
765:       PetscCall(PetscFree(A->factorprefix));
766:       PetscCall(PetscStrallocpy(prefix, &A->factorprefix));
767:     }
768:   } else PetscCall(PetscFree(A->factorprefix));
769:   PetscFunctionReturn(PETSC_SUCCESS);
770: }

772: /*@
773:   MatAppendOptionsPrefixFactor - Appends to the prefix used for searching for all matrix factor options in the database for
774:   for matrices created with `MatGetFactor()`

776:   Logically Collective

778:   Input Parameters:
779: + A      - the matrix
780: - prefix - the prefix to prepend to all option names for the factored matrix

782:   Level: developer

784:   Notes:
785:   A hyphen (-) must NOT be given at the beginning of the prefix name.
786:   The first character of all runtime options is AUTOMATICALLY the hyphen.

788:   Normally the prefix is automatically passed in from the `PC` calling the factorization. To set
789:   it directly when not using `KSP`/`PC` use  `MatAppendOptionsPrefixFactor()`

791: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `PetscOptionsCreate()`, `PetscOptionsDestroy()`, `PetscObjectSetOptionsPrefix()`, `PetscObjectPrependOptionsPrefix()`,
792:           `PetscObjectGetOptionsPrefix()`, `TSAppendOptionsPrefix()`, `SNESAppendOptionsPrefix()`, `KSPAppendOptionsPrefix()`, `MatSetOptionsPrefixFactor()`,
793:           `MatSetOptionsPrefix()`
794: @*/
795: PetscErrorCode MatAppendOptionsPrefixFactor(Mat A, const char prefix[])
796: {
797:   size_t len1, len2, new_len;

799:   PetscFunctionBegin;
801:   if (!prefix) PetscFunctionReturn(PETSC_SUCCESS);
802:   if (!A->factorprefix) {
803:     PetscCall(MatSetOptionsPrefixFactor(A, prefix));
804:     PetscFunctionReturn(PETSC_SUCCESS);
805:   }
806:   PetscCheck(prefix[0] != '-', PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Options prefix should not begin with a hyphen");

808:   PetscCall(PetscStrlen(A->factorprefix, &len1));
809:   PetscCall(PetscStrlen(prefix, &len2));
810:   new_len = len1 + len2 + 1;
811:   PetscCall(PetscRealloc(new_len * sizeof(*A->factorprefix), &A->factorprefix));
812:   PetscCall(PetscStrncpy(A->factorprefix + len1, prefix, len2 + 1));
813:   PetscFunctionReturn(PETSC_SUCCESS);
814: }

816: /*@
817:   MatAppendOptionsPrefix - Appends to the prefix used for searching for all
818:   matrix options in the database.

820:   Logically Collective

822:   Input Parameters:
823: + A      - the matrix
824: - prefix - the prefix to prepend to all option names

826:   Level: advanced

828:   Note:
829:   A hyphen (-) must NOT be given at the beginning of the prefix name.
830:   The first character of all runtime options is AUTOMATICALLY the hyphen.

832: .seealso: [](ch_matrices), `Mat`, `MatGetOptionsPrefix()`, `MatAppendOptionsPrefixFactor()`, `MatSetOptionsPrefix()`
833: @*/
834: PetscErrorCode MatAppendOptionsPrefix(Mat A, const char prefix[])
835: {
836:   PetscFunctionBegin;
838:   PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)A, prefix));
839:   PetscFunctionReturn(PETSC_SUCCESS);
840: }

842: /*@
843:   MatGetOptionsPrefix - Gets the prefix used for searching for all
844:   matrix options in the database.

846:   Not Collective

848:   Input Parameter:
849: . A - the matrix

851:   Output Parameter:
852: . prefix - pointer to the prefix string used

854:   Level: advanced

856:   Fortran Note:
857:   The user should pass in a string `prefix` of
858:   sufficient length to hold the prefix.

860: .seealso: [](ch_matrices), `Mat`, `MatAppendOptionsPrefix()`, `MatSetOptionsPrefix()`, `MatAppendOptionsPrefixFactor()`, `MatSetOptionsPrefixFactor()`
861: @*/
862: PetscErrorCode MatGetOptionsPrefix(Mat A, const char *prefix[])
863: {
864:   PetscFunctionBegin;
866:   PetscAssertPointer(prefix, 2);
867:   PetscCall(PetscObjectGetOptionsPrefix((PetscObject)A, prefix));
868:   PetscFunctionReturn(PETSC_SUCCESS);
869: }

871: /*@
872:   MatGetState - Gets the state of a `Mat`. Same value as returned by `PetscObjectStateGet()`

874:   Not Collective

876:   Input Parameter:
877: . A - the matrix

879:   Output Parameter:
880: . state - the object state

882:   Level: advanced

884:   Note:
885:   Object state is an integer which gets increased every time
886:   the object is changed. By saving and later querying the object state
887:   one can determine whether information about the object is still current.

889:   See `MatGetNonzeroState()` to determine if the nonzero structure of the matrix has changed.

891: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `PetscObjectStateGet()`, `MatGetNonzeroState()`
892: @*/
893: PetscErrorCode MatGetState(Mat A, PetscObjectState *state)
894: {
895:   PetscFunctionBegin;
897:   PetscAssertPointer(state, 2);
898:   PetscCall(PetscObjectStateGet((PetscObject)A, state));
899:   PetscFunctionReturn(PETSC_SUCCESS);
900: }

902: /*@
903:   MatResetPreallocation - Reset matrix to use the original preallocation values provided by the user, for example with `MatXAIJSetPreallocation()`

905:   Collective

907:   Input Parameter:
908: . A - the matrix

910:   Level: beginner

912:   Notes:
913:   After calling `MatAssemblyBegin()` and `MatAssemblyEnd()` with `MAT_FINAL_ASSEMBLY` the matrix data structures represent the nonzeros assigned to the
914:   matrix. If that space is less than the preallocated space that extra preallocated space is no longer available to take on new values. `MatResetPreallocation()`
915:   makes all of the preallocation space available

917:   Current values in the matrix are lost in this call

919:   Currently only supported for  `MATAIJ` matrices.

921: .seealso: [](ch_matrices), `Mat`, `MatSeqAIJSetPreallocation()`, `MatMPIAIJSetPreallocation()`, `MatXAIJSetPreallocation()`
922: @*/
923: PetscErrorCode MatResetPreallocation(Mat A)
924: {
925:   PetscFunctionBegin;
928:   PetscUseMethod(A, "MatResetPreallocation_C", (Mat), (A));
929:   PetscFunctionReturn(PETSC_SUCCESS);
930: }

932: /*@
933:   MatSetUp - Sets up the internal matrix data structures for later use by the matrix

935:   Collective

937:   Input Parameter:
938: . A - the matrix

940:   Level: advanced

942:   Notes:
943:   If the user has not set preallocation for this matrix then an efficient algorithm will be used for the first round of
944:   setting values in the matrix.

946:   This routine is called internally by other `Mat` functions when needed so rarely needs to be called by users

948: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatCreate()`, `MatDestroy()`, `MatXAIJSetPreallocation()`
949: @*/
950: PetscErrorCode MatSetUp(Mat A)
951: {
952:   PetscFunctionBegin;
954:   if (!((PetscObject)A)->type_name) {
955:     PetscMPIInt size;

957:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size));
958:     PetscCall(MatSetType(A, size == 1 ? MATSEQAIJ : MATMPIAIJ));
959:   }
960:   if (!A->preallocated) PetscTryTypeMethod(A, setup);
961:   PetscCall(PetscLayoutSetUp(A->rmap));
962:   PetscCall(PetscLayoutSetUp(A->cmap));
963:   A->preallocated = PETSC_TRUE;
964:   PetscFunctionReturn(PETSC_SUCCESS);
965: }

967: #if defined(PETSC_HAVE_SAWS)
968: #include <petscviewersaws.h>
969: #endif

971: /*
972:    If threadsafety is on extraneous matrices may be printed

974:    This flag cannot be stored in the matrix because the original matrix in MatView() may assemble a new matrix which is passed into MatViewFromOptions()
975: */
976: #if !defined(PETSC_HAVE_THREADSAFETY)
977: static PetscInt insidematview = 0;
978: #endif

980: /*@
981:   MatViewFromOptions - View properties of the matrix based on options set in the options database

983:   Collective

985:   Input Parameters:
986: + A    - the matrix
987: . obj  - optional additional object that provides the options prefix to use
988: - name - command line option

990:   Options Database Key:
991: . -mat_view [viewertype]:... - the viewer and its options

993:   Level: intermediate

995:   Note:
996: .vb
997:     If no value is provided ascii:stdout is used
998:        ascii[:[filename][:[format][:append]]]    defaults to stdout - format can be one of ascii_info, ascii_info_detail, or ascii_matlab,
999:                                                   for example ascii::ascii_info prints just the information about the object not all details
1000:                                                   unless :append is given filename opens in write mode, overwriting what was already there
1001:        binary[:[filename][:[format][:append]]]   defaults to the file binaryoutput
1002:        draw[:drawtype[:filename]]                for example, draw:tikz, draw:tikz:figure.tex  or draw:x
1003:        socket[:port]                             defaults to the standard output port
1004:        saws[:communicatorname]                    publishes object to the Scientific Application Webserver (SAWs)
1005: .ve

1007: .seealso: [](ch_matrices), `Mat`, `MatView()`, `PetscObjectViewFromOptions()`, `MatCreate()`
1008: @*/
1009: PetscErrorCode MatViewFromOptions(Mat A, PetscObject obj, const char name[])
1010: {
1011:   PetscFunctionBegin;
1013: #if !defined(PETSC_HAVE_THREADSAFETY)
1014:   if (insidematview) PetscFunctionReturn(PETSC_SUCCESS);
1015: #endif
1016:   PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
1017:   PetscFunctionReturn(PETSC_SUCCESS);
1018: }

1020: /*@
1021:   MatView - display information about a matrix in a variety ways

1023:   Collective on viewer

1025:   Input Parameters:
1026: + mat    - the matrix
1027: - viewer - visualization context

1029:   Options Database Keys:
1030: + -mat_view ::ascii_info           - Prints info on matrix at conclusion of `MatAssemblyEnd()`
1031: . -mat_view ::ascii_info_detail    - Prints more detailed info
1032: . -mat_view                        - Prints matrix in ASCII format
1033: . -mat_view ::ascii_matlab         - Prints matrix in MATLAB format
1034: . -mat_view draw                   - PetscDraws nonzero structure of matrix, using `MatView()` and `PetscDrawOpenX()`.
1035: . -display <name>                  - Sets display name (default is host)
1036: . -draw_pause <sec>                - Sets number of seconds to pause after display
1037: . -mat_view socket                 - Sends matrix to socket, can be accessed from MATLAB (see Users-Manual: ch_matlab for details)
1038: . -viewer_socket_machine <machine> - -
1039: . -viewer_socket_port <port>       - -
1040: . -mat_view binary                 - save matrix to file in binary format
1041: - -viewer_binary_filename <name>   - -

1043:   Level: beginner

1045:   Notes:
1046:   The available visualization contexts include
1047: +    `PETSC_VIEWER_STDOUT_SELF`   - for sequential matrices
1048: .    `PETSC_VIEWER_STDOUT_WORLD`  - for parallel matrices created on `PETSC_COMM_WORLD`
1049: .    `PETSC_VIEWER_STDOUT_`(comm) - for matrices created on MPI communicator comm
1050: -     `PETSC_VIEWER_DRAW_WORLD`   - graphical display of nonzero structure

1052:   The user can open alternative visualization contexts with
1053: +    `PetscViewerASCIIOpen()`  - Outputs matrix to a specified file
1054: .    `PetscViewerBinaryOpen()` - Outputs matrix in binary to a  specified file; corresponding input uses `MatLoad()`
1055: .    `PetscViewerDrawOpen()`   - Outputs nonzero matrix nonzero structure to an X window display
1056: -    `PetscViewerSocketOpen()` - Outputs matrix to Socket viewer, `PETSCVIEWERSOCKET`. Only the `MATSEQDENSE` and `MATAIJ` types support this viewer.

1058:   The user can call `PetscViewerPushFormat()` to specify the output
1059:   format of ASCII printed objects (when using `PETSC_VIEWER_STDOUT_SELF`,
1060:   `PETSC_VIEWER_STDOUT_WORLD` and `PetscViewerASCIIOpen()`).  Available formats include
1061: +    `PETSC_VIEWER_DEFAULT`           - default, prints matrix contents
1062: .    `PETSC_VIEWER_ASCII_MATLAB`      - prints matrix contents in MATLAB format
1063: .    `PETSC_VIEWER_ASCII_DENSE`       - prints entire matrix including zeros
1064: .    `PETSC_VIEWER_ASCII_COMMON`      - prints matrix contents, using a sparse  format common among all matrix types
1065: .    `PETSC_VIEWER_ASCII_IMPL`        - prints matrix contents, using an implementation-specific format (which is in many cases the same as the default)
1066: .    `PETSC_VIEWER_ASCII_INFO`        - prints basic information about the matrix size and structure (not the matrix entries)
1067: -    `PETSC_VIEWER_ASCII_INFO_DETAIL` - prints more detailed information about the matrix nonzero structure (still not vector or matrix entries)

1069:   The ASCII viewers are only recommended for small matrices on at most a moderate number of processes,
1070:   the program will seemingly hang and take hours for larger matrices, for larger matrices one should use the binary format.

1072:   In the debugger you can do "call MatView(mat,0)" to display the matrix. (The same holds for any PETSc object viewer).

1074:   See the manual page for `MatLoad()` for the exact format of the binary file when the binary
1075:   viewer is used.

1077:   See share/petsc/matlab/PetscBinaryRead.m for a MATLAB code that can read in the binary file when the binary
1078:   viewer is used and lib/petsc/bin/PetscBinaryIO.py for loading them into Python.

1080:   One can use '-mat_view draw -draw_pause -1' to pause the graphical display of matrix nonzero structure,
1081:   and then use the following mouse functions.
1082: .vb
1083:   left mouse: zoom in
1084:   middle mouse: zoom out
1085:   right mouse: continue with the simulation
1086: .ve

1088: .seealso: [](ch_matrices), `Mat`, `PetscViewerPushFormat()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscViewer`,
1089:           `PetscViewerSocketOpen()`, `PetscViewerBinaryOpen()`, `MatLoad()`, `MatViewFromOptions()`
1090: @*/
1091: PetscErrorCode MatView(Mat mat, PetscViewer viewer)
1092: {
1093:   PetscInt          rows, cols, rbs, cbs;
1094:   PetscBool         isascii, isstring, issaws;
1095:   PetscViewerFormat format;
1096:   PetscMPIInt       size;

1098:   PetscFunctionBegin;
1101:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)mat), &viewer));

1104:   PetscCall(PetscViewerGetFormat(viewer, &format));
1105:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)viewer), &size));
1106:   if (size == 1 && format == PETSC_VIEWER_LOAD_BALANCE) PetscFunctionReturn(PETSC_SUCCESS);

1108: #if !defined(PETSC_HAVE_THREADSAFETY)
1109:   insidematview++;
1110: #endif
1111:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
1112:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
1113:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSAWS, &issaws));
1114:   PetscCheck((isascii && (format == PETSC_VIEWER_ASCII_INFO || format == PETSC_VIEWER_ASCII_INFO_DETAIL)) || !mat->factortype, PetscObjectComm((PetscObject)viewer), PETSC_ERR_ARG_WRONGSTATE, "No viewers for factored matrix except ASCII, info, or info_detail");

1116:   PetscCall(PetscLogEventBegin(MAT_View, mat, viewer, 0, 0));
1117:   if (isascii) {
1118:     if (!mat->preallocated) {
1119:       PetscCall(PetscViewerASCIIPrintf(viewer, "Matrix has not been preallocated yet\n"));
1120: #if !defined(PETSC_HAVE_THREADSAFETY)
1121:       insidematview--;
1122: #endif
1123:       PetscCall(PetscLogEventEnd(MAT_View, mat, viewer, 0, 0));
1124:       PetscFunctionReturn(PETSC_SUCCESS);
1125:     }
1126:     if (!mat->assembled) {
1127:       PetscCall(PetscViewerASCIIPrintf(viewer, "Matrix has not been assembled yet\n"));
1128: #if !defined(PETSC_HAVE_THREADSAFETY)
1129:       insidematview--;
1130: #endif
1131:       PetscCall(PetscLogEventEnd(MAT_View, mat, viewer, 0, 0));
1132:       PetscFunctionReturn(PETSC_SUCCESS);
1133:     }
1134:     PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)mat, viewer));
1135:     if (format == PETSC_VIEWER_ASCII_INFO || format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
1136:       MatNullSpace nullsp, transnullsp;

1138:       PetscCall(PetscViewerASCIIPushTab(viewer));
1139:       PetscCall(MatGetSize(mat, &rows, &cols));
1140:       PetscCall(MatGetBlockSizes(mat, &rbs, &cbs));
1141:       if (rbs != 1 || cbs != 1) {
1142:         if (rbs != cbs) PetscCall(PetscViewerASCIIPrintf(viewer, "rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT ", rbs=%" PetscInt_FMT ", cbs=%" PetscInt_FMT "%s\n", rows, cols, rbs, cbs, mat->bsizes ? " variable blocks set" : ""));
1143:         else PetscCall(PetscViewerASCIIPrintf(viewer, "rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT ", bs=%" PetscInt_FMT "%s\n", rows, cols, rbs, mat->bsizes ? " variable blocks set" : ""));
1144:       } else PetscCall(PetscViewerASCIIPrintf(viewer, "rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT "\n", rows, cols));
1145:       if (mat->factortype) {
1146:         MatSolverType solver;
1147:         PetscCall(MatFactorGetSolverType(mat, &solver));
1148:         PetscCall(PetscViewerASCIIPrintf(viewer, "package used to perform factorization: %s\n", solver));
1149:       }
1150:       if (mat->ops->getinfo) {
1151:         MatInfo info;
1152:         PetscCall(MatGetInfo(mat, MAT_GLOBAL_SUM, &info));
1153:         PetscCall(PetscViewerASCIIPrintf(viewer, "total: nonzeros=%.f, allocated nonzeros=%.f\n", info.nz_used, info.nz_allocated));
1154:         if (!mat->factortype) PetscCall(PetscViewerASCIIPrintf(viewer, "total number of mallocs used during MatSetValues calls=%" PetscInt_FMT "\n", (PetscInt)info.mallocs));
1155:       }
1156:       PetscCall(MatGetNullSpace(mat, &nullsp));
1157:       PetscCall(MatGetTransposeNullSpace(mat, &transnullsp));
1158:       if (nullsp) PetscCall(PetscViewerASCIIPrintf(viewer, "  has attached null space\n"));
1159:       if (transnullsp && transnullsp != nullsp) PetscCall(PetscViewerASCIIPrintf(viewer, "  has attached transposed null space\n"));
1160:       PetscCall(MatGetNearNullSpace(mat, &nullsp));
1161:       if (nullsp) PetscCall(PetscViewerASCIIPrintf(viewer, "  has attached near null space\n"));
1162:       PetscCall(PetscViewerASCIIPushTab(viewer));
1163:       PetscCall(MatProductView(mat, viewer));
1164:       PetscCall(PetscViewerASCIIPopTab(viewer));
1165:       if (mat->bsizes && format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
1166:         IS tmp;

1168:         PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)viewer), mat->nblocks, mat->bsizes, PETSC_USE_POINTER, &tmp));
1169:         PetscCall(PetscObjectSetName((PetscObject)tmp, "Block Sizes"));
1170:         PetscCall(PetscViewerASCIIPushTab(viewer));
1171:         PetscCall(ISView(tmp, viewer));
1172:         PetscCall(PetscViewerASCIIPopTab(viewer));
1173:         PetscCall(ISDestroy(&tmp));
1174:       }
1175:     }
1176:   } else if (issaws) {
1177: #if defined(PETSC_HAVE_SAWS)
1178:     PetscMPIInt rank;

1180:     PetscCall(PetscObjectName((PetscObject)mat));
1181:     PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
1182:     if (!((PetscObject)mat)->amsmem && rank == 0) PetscCall(PetscObjectViewSAWs((PetscObject)mat, viewer));
1183: #endif
1184:   } else if (isstring) {
1185:     const char *type;
1186:     PetscCall(MatGetType(mat, &type));
1187:     PetscCall(PetscViewerStringSPrintf(viewer, " MatType: %-7.7s", type));
1188:     PetscTryTypeMethod(mat, view, viewer);
1189:   }
1190:   if ((format == PETSC_VIEWER_NATIVE || format == PETSC_VIEWER_LOAD_BALANCE) && mat->ops->viewnative) {
1191:     PetscCall(PetscViewerASCIIPushTab(viewer));
1192:     PetscUseTypeMethod(mat, viewnative, viewer);
1193:     PetscCall(PetscViewerASCIIPopTab(viewer));
1194:   } else if (mat->ops->view) {
1195:     PetscCall(PetscViewerASCIIPushTab(viewer));
1196:     PetscUseTypeMethod(mat, view, viewer);
1197:     PetscCall(PetscViewerASCIIPopTab(viewer));
1198:   }
1199:   if (isascii) {
1200:     PetscCall(PetscViewerGetFormat(viewer, &format));
1201:     if (format == PETSC_VIEWER_ASCII_INFO || format == PETSC_VIEWER_ASCII_INFO_DETAIL) PetscCall(PetscViewerASCIIPopTab(viewer));
1202:   }
1203:   PetscCall(PetscLogEventEnd(MAT_View, mat, viewer, 0, 0));
1204: #if !defined(PETSC_HAVE_THREADSAFETY)
1205:   insidematview--;
1206: #endif
1207:   PetscFunctionReturn(PETSC_SUCCESS);
1208: }

1210: #if defined(PETSC_USE_DEBUG)
1211: #include <../src/sys/totalview/tv_data_display.h>
1212: PETSC_UNUSED static int TV_display_type(const struct _p_Mat *mat)
1213: {
1214:   TV_add_row("Local rows", "int", &mat->rmap->n);
1215:   TV_add_row("Local columns", "int", &mat->cmap->n);
1216:   TV_add_row("Global rows", "int", &mat->rmap->N);
1217:   TV_add_row("Global columns", "int", &mat->cmap->N);
1218:   TV_add_row("Typename", TV_ascii_string_type, ((PetscObject)mat)->type_name);
1219:   return TV_format_OK;
1220: }
1221: #endif

1223: /*@
1224:   MatLoad - Loads a matrix that has been stored in binary/HDF5 format
1225:   with `MatView()`.  The matrix format is determined from the options database.
1226:   Generates a parallel MPI matrix if the communicator has more than one
1227:   processor.  The default matrix type is `MATAIJ`.

1229:   Collective

1231:   Input Parameters:
1232: + mat    - the newly loaded matrix, this needs to have been created with `MatCreate()`
1233:             or some related function before a call to `MatLoad()`
1234: - viewer - `PETSCVIEWERBINARY`/`PETSCVIEWERHDF5` file viewer

1236:   Options Database Key:
1237: . -matload_block_size <bs> - set block size

1239:   Level: beginner

1241:   Notes:
1242:   If the `Mat` type has not yet been given then `MATAIJ` is used, call `MatSetFromOptions()` on the
1243:   `Mat` before calling this routine if you wish to set it from the options database.

1245:   `MatLoad()` automatically loads into the options database any options
1246:   given in the file filename.info where filename is the name of the file
1247:   that was passed to the `PetscViewerBinaryOpen()`. The options in the info
1248:   file will be ignored if you use the -viewer_binary_skip_info option.

1250:   If the type or size of mat is not set before a call to `MatLoad()`, PETSc
1251:   sets the default matrix type AIJ and sets the local and global sizes.
1252:   If type and/or size is already set, then the same are used.

1254:   In parallel, each processor can load a subset of rows (or the
1255:   entire matrix).  This routine is especially useful when a large
1256:   matrix is stored on disk and only part of it is desired on each
1257:   processor.  For example, a parallel solver may access only some of
1258:   the rows from each processor.  The algorithm used here reads
1259:   relatively small blocks of data rather than reading the entire
1260:   matrix and then subsetting it.

1262:   Viewer's `PetscViewerType` must be either `PETSCVIEWERBINARY` or `PETSCVIEWERHDF5`.
1263:   Such viewer can be created using `PetscViewerBinaryOpen()` or `PetscViewerHDF5Open()`,
1264:   or the sequence like
1265: .vb
1266:     `PetscViewer` v;
1267:     `PetscViewerCreate`(`PETSC_COMM_WORLD`,&v);
1268:     `PetscViewerSetType`(v,`PETSCVIEWERBINARY`);
1269:     `PetscViewerSetFromOptions`(v);
1270:     `PetscViewerFileSetMode`(v,`FILE_MODE_READ`);
1271:     `PetscViewerFileSetName`(v,"datafile");
1272: .ve
1273:   The optional `PetscViewerSetFromOptions()` call allows overriding `PetscViewerSetType()` using the option
1274: $ -viewer_type {binary, hdf5}

1276:   See the example src/ksp/ksp/tutorials/ex27.c with the first approach,
1277:   and src/mat/tutorials/ex10.c with the second approach.

1279:   In case of `PETSCVIEWERBINARY`, a native PETSc binary format is used. Each of the blocks
1280:   is read onto MPI rank 0 and then shipped to its destination MPI rank, one after another.
1281:   Multiple objects, both matrices and vectors, can be stored within the same file.
1282:   Their `PetscObject` name is ignored; they are loaded in the order of their storage.

1284:   Most users should not need to know the details of the binary storage
1285:   format, since `MatLoad()` and `MatView()` completely hide these details.
1286:   But for anyone who is interested, the standard binary matrix storage
1287:   format is

1289: .vb
1290:     PetscInt    MAT_FILE_CLASSID
1291:     PetscInt    number of rows
1292:     PetscInt    number of columns
1293:     PetscInt    total number of nonzeros
1294:     PetscInt    *number nonzeros in each row
1295:     PetscInt    *column indices of all nonzeros (starting index is zero)
1296:     PetscScalar *values of all nonzeros
1297: .ve
1298:   If PETSc was not configured with `--with-64-bit-indices` then only `MATMPIAIJ` matrices with more than `PETSC_INT_MAX` non-zeros can be
1299:   stored or loaded (each MPI process part of the matrix must have less than `PETSC_INT_MAX` nonzeros). Since the total nonzero count in this
1300:   case will not fit in a (32-bit) `PetscInt` the value `PETSC_INT_MAX` is used for the header entry `total number of nonzeros`.

1302:   PETSc automatically does the byte swapping for
1303:   machines that store the bytes reversed. Thus if you write your own binary
1304:   read/write routines you have to swap the bytes; see `PetscBinaryRead()`
1305:   and `PetscBinaryWrite()` to see how this may be done.

1307:   In case of `PETSCVIEWERHDF5`, a parallel HDF5 reader is used.
1308:   Each processor's chunk is loaded independently by its owning MPI process.
1309:   Multiple objects, both matrices and vectors, can be stored within the same file.
1310:   They are looked up by their PetscObject name.

1312:   As the MATLAB MAT-File Version 7.3 format is also a HDF5 flavor, we decided to use
1313:   by default the same structure and naming of the AIJ arrays and column count
1314:   within the HDF5 file. This means that a MAT file saved with -v7.3 flag, e.g.
1315: $    save example.mat A b -v7.3
1316:   can be directly read by this routine (see Reference 1 for details).

1318:   Depending on your MATLAB version, this format might be a default,
1319:   otherwise you can set it as default in Preferences.

1321:   Unless -nocompression flag is used to save the file in MATLAB,
1322:   PETSc must be configured with ZLIB package.

1324:   See also examples src/mat/tutorials/ex10.c and src/ksp/ksp/tutorials/ex27.c

1326:   This reader currently supports only real `MATSEQAIJ`, `MATMPIAIJ`, `MATSEQDENSE` and `MATMPIDENSE` matrices for `PETSCVIEWERHDF5`

1328:   Corresponding `MatView()` is not yet implemented.

1330:   The loaded matrix is actually a transpose of the original one in MATLAB,
1331:   unless you push `PETSC_VIEWER_HDF5_MAT` format (see examples above).
1332:   With this format, matrix is automatically transposed by PETSc,
1333:   unless the matrix is marked as SPD or symmetric
1334:   (see `MatSetOption()`, `MAT_SPD`, `MAT_SYMMETRIC`).

1336:   See MATLAB Documentation on `save()`, <https://www.mathworks.com/help/matlab/ref/save.html#btox10b-1-version>

1338: .seealso: [](ch_matrices), `Mat`, `PetscViewerBinaryOpen()`, `PetscViewerSetType()`, `MatView()`, `VecLoad()`
1339:  @*/
1340: PetscErrorCode MatLoad(Mat mat, PetscViewer viewer)
1341: {
1342:   PetscBool flg;

1344:   PetscFunctionBegin;

1348:   if (!((PetscObject)mat)->type_name) PetscCall(MatSetType(mat, MATAIJ));

1350:   flg = PETSC_FALSE;
1351:   PetscCall(PetscOptionsGetBool(((PetscObject)mat)->options, ((PetscObject)mat)->prefix, "-matload_symmetric", &flg, NULL));
1352:   if (flg) {
1353:     PetscCall(MatSetOption(mat, MAT_SYMMETRIC, PETSC_TRUE));
1354:     PetscCall(MatSetOption(mat, MAT_SYMMETRY_ETERNAL, PETSC_TRUE));
1355:   }
1356:   flg = PETSC_FALSE;
1357:   PetscCall(PetscOptionsGetBool(((PetscObject)mat)->options, ((PetscObject)mat)->prefix, "-matload_spd", &flg, NULL));
1358:   if (flg) PetscCall(MatSetOption(mat, MAT_SPD, PETSC_TRUE));

1360:   PetscCall(PetscLogEventBegin(MAT_Load, mat, viewer, 0, 0));
1361:   PetscUseTypeMethod(mat, load, viewer);
1362:   PetscCall(PetscLogEventEnd(MAT_Load, mat, viewer, 0, 0));
1363:   PetscFunctionReturn(PETSC_SUCCESS);
1364: }

1366: static PetscErrorCode MatDestroy_Redundant(Mat_Redundant **redundant)
1367: {
1368:   Mat_Redundant *redund = *redundant;

1370:   PetscFunctionBegin;
1371:   if (redund) {
1372:     if (redund->matseq) { /* via MatCreateSubMatrices()  */
1373:       PetscCall(ISDestroy(&redund->isrow));
1374:       PetscCall(ISDestroy(&redund->iscol));
1375:       PetscCall(MatDestroySubMatrices(1, &redund->matseq));
1376:     } else {
1377:       PetscCall(PetscFree2(redund->send_rank, redund->recv_rank));
1378:       PetscCall(PetscFree(redund->sbuf_j));
1379:       PetscCall(PetscFree(redund->sbuf_a));
1380:       for (PetscInt i = 0; i < redund->nrecvs; i++) {
1381:         PetscCall(PetscFree(redund->rbuf_j[i]));
1382:         PetscCall(PetscFree(redund->rbuf_a[i]));
1383:       }
1384:       PetscCall(PetscFree4(redund->sbuf_nz, redund->rbuf_nz, redund->rbuf_j, redund->rbuf_a));
1385:     }

1387:     if (redund->subcomm) PetscCall(PetscCommDestroy(&redund->subcomm));
1388:     PetscCall(PetscFree(redund));
1389:   }
1390:   PetscFunctionReturn(PETSC_SUCCESS);
1391: }

1393: /*@
1394:   MatDestroy - Frees space taken by a matrix.

1396:   Collective

1398:   Input Parameter:
1399: . A - the matrix

1401:   Level: beginner

1403:   Developer Note:
1404:   Some special arrays of matrices are not destroyed in this routine but instead by the routines called by
1405:   `MatDestroySubMatrices()`. Thus one must be sure that any changes here must also be made in those routines.
1406:   `MatHeaderMerge()` and `MatHeaderReplace()` also manipulate the data in the `Mat` object and likely need changes
1407:   if changes are needed here.

1409: .seealso: [](ch_matrices), `Mat`, `MatCreate()`
1410: @*/
1411: PetscErrorCode MatDestroy(Mat *A)
1412: {
1413:   PetscFunctionBegin;
1414:   if (!*A) PetscFunctionReturn(PETSC_SUCCESS);
1416:   if (--((PetscObject)*A)->refct > 0) {
1417:     *A = NULL;
1418:     PetscFunctionReturn(PETSC_SUCCESS);
1419:   }

1421:   /* if memory was published with SAWs then destroy it */
1422:   PetscCall(PetscObjectSAWsViewOff((PetscObject)*A));
1423:   PetscTryTypeMethod(*A, destroy);

1425:   PetscCall(PetscFree((*A)->factorprefix));
1426:   PetscCall(PetscFree((*A)->defaultvectype));
1427:   PetscCall(PetscFree((*A)->defaultrandtype));
1428:   PetscCall(PetscFree((*A)->bsizes));
1429:   PetscCall(PetscFree((*A)->solvertype));
1430:   for (PetscInt i = 0; i < MAT_FACTOR_NUM_TYPES; i++) PetscCall(PetscFree((*A)->preferredordering[i]));
1431:   if ((*A)->redundant && (*A)->redundant->matseq[0] == *A) (*A)->redundant->matseq[0] = NULL;
1432:   PetscCall(MatDestroy_Redundant(&(*A)->redundant));
1433:   PetscCall(MatProductClear(*A));
1434:   PetscCall(MatNullSpaceDestroy(&(*A)->nullsp));
1435:   PetscCall(MatNullSpaceDestroy(&(*A)->transnullsp));
1436:   PetscCall(MatNullSpaceDestroy(&(*A)->nearnullsp));
1437:   PetscCall(MatDestroy(&(*A)->schur));
1438:   PetscCall(PetscLayoutDestroy(&(*A)->rmap));
1439:   PetscCall(PetscLayoutDestroy(&(*A)->cmap));
1440:   PetscCall(PetscHeaderDestroy(A));
1441:   PetscFunctionReturn(PETSC_SUCCESS);
1442: }

1444: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
1445: /*@
1446:   MatSetValues - Inserts or adds a block of values into a matrix.
1447:   These values may be cached, so `MatAssemblyBegin()` and `MatAssemblyEnd()`
1448:   MUST be called after all calls to `MatSetValues()` have been completed.

1450:   Not Collective

1452:   Input Parameters:
1453: + mat  - the matrix
1454: . v    - a logically two-dimensional array of values
1455: . m    - the number of rows
1456: . idxm - the global indices of the rows
1457: . n    - the number of columns
1458: . idxn - the global indices of the columns
1459: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` to replace existing entries with new values

1461:   Level: beginner

1463:   Notes:
1464:   By default the values, `v`, are stored row-oriented. See `MatSetOption()` for other options.

1466:   Calls to `MatSetValues()` with the `INSERT_VALUES` and `ADD_VALUES`
1467:   options cannot be mixed without intervening calls to the assembly
1468:   routines.

1470:   `MatSetValues()` uses 0-based row and column numbers in Fortran
1471:   as well as in C.

1473:   Negative indices may be passed in `idxm` and `idxn`, these rows and columns are
1474:   simply ignored. This allows easily inserting element stiffness matrices
1475:   with homogeneous Dirichlet boundary conditions that you don't want represented
1476:   in the matrix.

1478:   Efficiency Alert:
1479:   The routine `MatSetValuesBlocked()` may offer much better efficiency
1480:   for users of block sparse formats (`MATSEQBAIJ` and `MATMPIBAIJ`).

1482:   Fortran Notes:
1483:   If any of `idxm`, `idxn`, and `v` are scalars pass them using, for example,
1484: .vb
1485:   MatSetValues(mat, one, [idxm], one, [idxn], [v], INSERT_VALUES)
1486: .ve

1488:   If `v` is a two-dimensional array use `reshape()` to pass it as a one dimensional array

1490:   Developer Note:
1491:   This is labeled with C so does not automatically generate Fortran stubs and interfaces
1492:   because it requires multiple Fortran interfaces depending on which arguments are scalar or arrays.

1494: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1495:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`
1496: @*/
1497: PetscErrorCode MatSetValues(Mat mat, PetscInt m, const PetscInt idxm[], PetscInt n, const PetscInt idxn[], const PetscScalar v[], InsertMode addv)
1498: {
1499:   PetscFunctionBeginHot;
1502:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
1503:   PetscAssertPointer(idxm, 3);
1504:   PetscAssertPointer(idxn, 5);
1505:   MatCheckPreallocated(mat, 1);

1507:   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
1508:   else PetscCheck(mat->insertmode == addv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add values and insert values");

1510:   if (PetscDefined(USE_DEBUG)) {
1511:     PetscInt i, j;

1513:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
1514:     if (v) {
1515:       for (i = 0; i < m; i++) {
1516:         for (j = 0; j < n; j++) {
1517:           if (mat->erroriffailure && PetscIsInfOrNanScalar(v[i * n + j]))
1518: #if defined(PETSC_USE_COMPLEX)
1519:             SETERRQ(PETSC_COMM_SELF, PETSC_ERR_FP, "Inserting %g+i%g at matrix entry (%" PetscInt_FMT ",%" PetscInt_FMT ")", (double)PetscRealPart(v[i * n + j]), (double)PetscImaginaryPart(v[i * n + j]), idxm[i], idxn[j]);
1520: #else
1521:             SETERRQ(PETSC_COMM_SELF, PETSC_ERR_FP, "Inserting %g at matrix entry (%" PetscInt_FMT ",%" PetscInt_FMT ")", (double)v[i * n + j], idxm[i], idxn[j]);
1522: #endif
1523:         }
1524:       }
1525:     }
1526:     for (i = 0; i < m; i++) PetscCheck(idxm[i] < mat->rmap->N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cannot insert in row %" PetscInt_FMT ", maximum is %" PetscInt_FMT, idxm[i], mat->rmap->N - 1);
1527:     for (i = 0; i < n; i++) PetscCheck(idxn[i] < mat->cmap->N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cannot insert in column %" PetscInt_FMT ", maximum is %" PetscInt_FMT, idxn[i], mat->cmap->N - 1);
1528:   }

1530:   if (mat->assembled) {
1531:     mat->was_assembled = PETSC_TRUE;
1532:     mat->assembled     = PETSC_FALSE;
1533:   }
1534:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
1535:   PetscUseTypeMethod(mat, setvalues, m, idxm, n, idxn, v, addv);
1536:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
1537:   PetscFunctionReturn(PETSC_SUCCESS);
1538: }

1540: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
1541: /*@
1542:   MatSetValuesIS - Inserts or adds a block of values into a matrix using an `IS` to indicate the rows and columns
1543:   These values may be cached, so `MatAssemblyBegin()` and `MatAssemblyEnd()`
1544:   MUST be called after all calls to `MatSetValues()` have been completed.

1546:   Not Collective

1548:   Input Parameters:
1549: + mat  - the matrix
1550: . v    - a logically two-dimensional array of values
1551: . ism  - the rows to provide
1552: . isn  - the columns to provide
1553: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` to replace existing entries with new values

1555:   Level: beginner

1557:   Notes:
1558:   By default the values, `v`, are stored row-oriented. See `MatSetOption()` for other options.

1560:   Calls to `MatSetValues()` with the `INSERT_VALUES` and `ADD_VALUES`
1561:   options cannot be mixed without intervening calls to the assembly
1562:   routines.

1564:   `MatSetValues()` uses 0-based row and column numbers in Fortran
1565:   as well as in C.

1567:   Negative indices may be passed in `ism` and `isn`, these rows and columns are
1568:   simply ignored. This allows easily inserting element stiffness matrices
1569:   with homogeneous Dirichlet boundary conditions that you don't want represented
1570:   in the matrix.

1572:   Efficiency Alert:
1573:   The routine `MatSetValuesBlocked()` may offer much better efficiency
1574:   for users of block sparse formats (`MATSEQBAIJ` and `MATMPIBAIJ`).

1576:   This is currently not optimized for any particular `ISType`

1578:   Developer Note:
1579:   This is labeled with C so does not automatically generate Fortran stubs and interfaces
1580:   because it requires multiple Fortran interfaces depending on which arguments are scalar or arrays.

1582: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatSetValues()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1583:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`
1584: @*/
1585: PetscErrorCode MatSetValuesIS(Mat mat, IS ism, IS isn, const PetscScalar v[], InsertMode addv)
1586: {
1587:   PetscInt        m, n;
1588:   const PetscInt *rows, *cols;

1590:   PetscFunctionBeginHot;
1592:   PetscCall(ISGetIndices(ism, &rows));
1593:   PetscCall(ISGetIndices(isn, &cols));
1594:   PetscCall(ISGetLocalSize(ism, &m));
1595:   PetscCall(ISGetLocalSize(isn, &n));
1596:   PetscCall(MatSetValues(mat, m, rows, n, cols, v, addv));
1597:   PetscCall(ISRestoreIndices(ism, &rows));
1598:   PetscCall(ISRestoreIndices(isn, &cols));
1599:   PetscFunctionReturn(PETSC_SUCCESS);
1600: }

1602: /*@
1603:   MatSetValuesRowLocal - Inserts a row (block row for `MATBAIJ` matrices) of nonzero
1604:   values into a matrix

1606:   Not Collective

1608:   Input Parameters:
1609: + mat - the matrix
1610: . row - the (block) row to set
1611: - v   - a logically two-dimensional array of values

1613:   Level: intermediate

1615:   Notes:
1616:   The values, `v`, are column-oriented (for the block version) and sorted

1618:   All the nonzero values in `row` must be provided

1620:   The matrix must have previously had its column indices set, likely by having been assembled.

1622:   `row` must belong to this MPI process

1624: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1625:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`, `MatSetValues()`, `MatSetValuesRow()`, `MatSetLocalToGlobalMapping()`
1626: @*/
1627: PetscErrorCode MatSetValuesRowLocal(Mat mat, PetscInt row, const PetscScalar v[])
1628: {
1629:   PetscInt globalrow;

1631:   PetscFunctionBegin;
1634:   PetscAssertPointer(v, 3);
1635:   PetscCall(ISLocalToGlobalMappingApply(mat->rmap->mapping, 1, &row, &globalrow));
1636:   PetscCall(MatSetValuesRow(mat, globalrow, v));
1637:   PetscFunctionReturn(PETSC_SUCCESS);
1638: }

1640: /*@
1641:   MatSetValuesRow - Inserts a row (block row for `MATBAIJ` matrices) of nonzero
1642:   values into a matrix

1644:   Not Collective

1646:   Input Parameters:
1647: + mat - the matrix
1648: . row - the (block) row to set
1649: - v   - a logically two-dimensional (column major) array of values for  block matrices with blocksize larger than one, otherwise a one dimensional array of values

1651:   Level: advanced

1653:   Notes:
1654:   The values, `v`, are column-oriented for the block version.

1656:   All the nonzeros in `row` must be provided

1658:   THE MATRIX MUST HAVE PREVIOUSLY HAD ITS COLUMN INDICES SET. IT IS RARE THAT THIS ROUTINE IS USED, usually `MatSetValues()` is used.

1660:   `row` must belong to this process

1662: .seealso: [](ch_matrices), `Mat`, `MatSetValues()`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1663:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`
1664: @*/
1665: PetscErrorCode MatSetValuesRow(Mat mat, PetscInt row, const PetscScalar v[])
1666: {
1667:   PetscFunctionBeginHot;
1670:   MatCheckPreallocated(mat, 1);
1671:   PetscAssertPointer(v, 3);
1672:   PetscCheck(mat->insertmode != ADD_VALUES, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add and insert values");
1673:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
1674:   mat->insertmode = INSERT_VALUES;

1676:   if (mat->assembled) {
1677:     mat->was_assembled = PETSC_TRUE;
1678:     mat->assembled     = PETSC_FALSE;
1679:   }
1680:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
1681:   PetscUseTypeMethod(mat, setvaluesrow, row, v);
1682:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
1683:   PetscFunctionReturn(PETSC_SUCCESS);
1684: }

1686: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
1687: /*@
1688:   MatSetValuesStencil - Inserts or adds a block of values into a matrix.
1689:   Using structured grid indexing

1691:   Not Collective

1693:   Input Parameters:
1694: + mat  - the matrix
1695: . m    - number of rows being entered
1696: . idxm - grid coordinates (and component number when dof > 1) for matrix rows being entered
1697: . n    - number of columns being entered
1698: . idxn - grid coordinates (and component number when dof > 1) for matrix columns being entered
1699: . v    - a logically two-dimensional array of values
1700: - addv - either `ADD_VALUES` to add to existing entries at that location or `INSERT_VALUES` to replace existing entries with new values

1702:   Level: beginner

1704:   Notes:
1705:   By default the values, `v`, are row-oriented.  See `MatSetOption()` for other options.

1707:   Calls to `MatSetValuesStencil()` with the `INSERT_VALUES` and `ADD_VALUES`
1708:   options cannot be mixed without intervening calls to the assembly
1709:   routines.

1711:   The grid coordinates are across the entire grid, not just the local portion

1713:   `MatSetValuesStencil()` uses 0-based row and column numbers in Fortran
1714:   as well as in C.

1716:   For setting/accessing vector values via array coordinates you can use the `DMDAVecGetArray()` routine

1718:   In order to use this routine you must either obtain the matrix with `DMCreateMatrix()`
1719:   or call `MatSetLocalToGlobalMapping()` and `MatSetStencil()` first.

1721:   The columns and rows in the stencil passed in MUST be contained within the
1722:   ghost region of the given process as set with DMDACreateXXX() or `MatSetStencil()`. For example,
1723:   if you create a `DMDA` with an overlap of one grid level and on a particular process its first
1724:   local nonghost x logical coordinate is 6 (so its first ghost x logical coordinate is 5) the
1725:   first i index you can use in your column and row indices in `MatSetStencil()` is 5.

1727:   For periodic boundary conditions use negative indices for values to the left (below 0; that are to be
1728:   obtained by wrapping values from right edge). For values to the right of the last entry using that index plus one
1729:   etc to obtain values that obtained by wrapping the values from the left edge. This does not work for anything but the
1730:   `DM_BOUNDARY_PERIODIC` boundary type.

1732:   For indices that don't mean anything for your case (like the k index when working in 2d) or the c index when you have
1733:   a single value per point) you can skip filling those indices.

1735:   Inspired by the structured grid interface to the HYPRE package
1736:   (https://computation.llnl.gov/projects/hypre-scalable-linear-solvers-multigrid-methods)

1738:   Efficiency Alert:
1739:   The routine `MatSetValuesBlockedStencil()` may offer much better efficiency
1740:   for users of block sparse formats (`MATSEQBAIJ` and `MATMPIBAIJ`).

1742:   Fortran Note:
1743:   `idxm` and `idxn` should be declared as
1744: $     MatStencil idxm(4,m),idxn(4,n)
1745:   and the values inserted using
1746: .vb
1747:     idxm(MatStencil_i,1) = i
1748:     idxm(MatStencil_j,1) = j
1749:     idxm(MatStencil_k,1) = k
1750:     idxm(MatStencil_c,1) = c
1751:     etc
1752: .ve

1754: .seealso: [](ch_matrices), `Mat`, `DMDA`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`
1755:           `MatSetValues()`, `MatSetValuesBlockedStencil()`, `MatSetStencil()`, `DMCreateMatrix()`, `DMDAVecGetArray()`, `MatStencil`
1756: @*/
1757: PetscErrorCode MatSetValuesStencil(Mat mat, PetscInt m, const MatStencil idxm[], PetscInt n, const MatStencil idxn[], const PetscScalar v[], InsertMode addv)
1758: {
1759:   PetscInt  buf[8192], *bufm = NULL, *bufn = NULL, *jdxm, *jdxn;
1760:   PetscInt  j, i, dim = mat->stencil.dim, *dims = mat->stencil.dims + 1, tmp;
1761:   PetscInt *starts = mat->stencil.starts, *dxm = (PetscInt *)idxm, *dxn = (PetscInt *)idxn, sdim = dim - (1 - (PetscInt)mat->stencil.noc);

1763:   PetscFunctionBegin;
1764:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
1767:   PetscAssertPointer(idxm, 3);
1768:   PetscAssertPointer(idxn, 5);

1770:   if ((m + n) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
1771:     jdxm = buf;
1772:     jdxn = buf + m;
1773:   } else {
1774:     PetscCall(PetscMalloc2(m, &bufm, n, &bufn));
1775:     jdxm = bufm;
1776:     jdxn = bufn;
1777:   }
1778:   for (i = 0; i < m; i++) {
1779:     for (j = 0; j < 3 - sdim; j++) dxm++;
1780:     tmp = *dxm++ - starts[0];
1781:     for (j = 0; j < dim - 1; j++) {
1782:       if ((*dxm++ - starts[j + 1]) < 0 || tmp < 0) tmp = -1;
1783:       else tmp = tmp * dims[j] + *(dxm - 1) - starts[j + 1];
1784:     }
1785:     if (mat->stencil.noc) dxm++;
1786:     jdxm[i] = tmp;
1787:   }
1788:   for (i = 0; i < n; i++) {
1789:     for (j = 0; j < 3 - sdim; j++) dxn++;
1790:     tmp = *dxn++ - starts[0];
1791:     for (j = 0; j < dim - 1; j++) {
1792:       if ((*dxn++ - starts[j + 1]) < 0 || tmp < 0) tmp = -1;
1793:       else tmp = tmp * dims[j] + *(dxn - 1) - starts[j + 1];
1794:     }
1795:     if (mat->stencil.noc) dxn++;
1796:     jdxn[i] = tmp;
1797:   }
1798:   PetscCall(MatSetValuesLocal(mat, m, jdxm, n, jdxn, v, addv));
1799:   PetscCall(PetscFree2(bufm, bufn));
1800:   PetscFunctionReturn(PETSC_SUCCESS);
1801: }

1803: /*@
1804:   MatSetValuesBlockedStencil - Inserts or adds a block of values into a matrix.
1805:   Using structured grid indexing

1807:   Not Collective

1809:   Input Parameters:
1810: + mat  - the matrix
1811: . m    - number of rows being entered
1812: . idxm - grid coordinates for matrix rows being entered
1813: . n    - number of columns being entered
1814: . idxn - grid coordinates for matrix columns being entered
1815: . v    - a logically two-dimensional array of values
1816: - addv - either `ADD_VALUES` to add to existing entries or `INSERT_VALUES` to replace existing entries with new values

1818:   Level: beginner

1820:   Notes:
1821:   By default the values, `v`, are row-oriented and unsorted.
1822:   See `MatSetOption()` for other options.

1824:   Calls to `MatSetValuesBlockedStencil()` with the `INSERT_VALUES` and `ADD_VALUES`
1825:   options cannot be mixed without intervening calls to the assembly
1826:   routines.

1828:   The grid coordinates are across the entire grid, not just the local portion

1830:   `MatSetValuesBlockedStencil()` uses 0-based row and column numbers in Fortran
1831:   as well as in C.

1833:   For setting/accessing vector values via array coordinates you can use the `DMDAVecGetArray()` routine

1835:   In order to use this routine you must either obtain the matrix with `DMCreateMatrix()`
1836:   or call `MatSetBlockSize()`, `MatSetLocalToGlobalMapping()` and `MatSetStencil()` first.

1838:   The columns and rows in the stencil passed in MUST be contained within the
1839:   ghost region of the given process as set with DMDACreateXXX() or `MatSetStencil()`. For example,
1840:   if you create a `DMDA` with an overlap of one grid level and on a particular process its first
1841:   local nonghost x logical coordinate is 6 (so its first ghost x logical coordinate is 5) the
1842:   first i index you can use in your column and row indices in `MatSetStencil()` is 5.

1844:   Negative indices may be passed in idxm and idxn, these rows and columns are
1845:   simply ignored. This allows easily inserting element stiffness matrices
1846:   with homogeneous Dirichlet boundary conditions that you don't want represented
1847:   in the matrix.

1849:   Inspired by the structured grid interface to the HYPRE package
1850:   (https://computation.llnl.gov/projects/hypre-scalable-linear-solvers-multigrid-methods)

1852:   Fortran Note:
1853:   `idxm` and `idxn` should be declared as
1854: $     MatStencil idxm(4,m),idxn(4,n)
1855:   and the values inserted using
1856: .vb
1857:     idxm(MatStencil_i,1) = i
1858:     idxm(MatStencil_j,1) = j
1859:     idxm(MatStencil_k,1) = k
1860:    etc
1861: .ve

1863: .seealso: [](ch_matrices), `Mat`, `DMDA`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`
1864:           `MatSetValues()`, `MatSetValuesStencil()`, `MatSetStencil()`, `DMCreateMatrix()`, `DMDAVecGetArray()`, `MatStencil`,
1865:           `MatSetBlockSize()`, `MatSetLocalToGlobalMapping()`
1866: @*/
1867: PetscErrorCode MatSetValuesBlockedStencil(Mat mat, PetscInt m, const MatStencil idxm[], PetscInt n, const MatStencil idxn[], const PetscScalar v[], InsertMode addv)
1868: {
1869:   PetscInt  buf[8192], *bufm = NULL, *bufn = NULL, *jdxm, *jdxn;
1870:   PetscInt  j, i, dim = mat->stencil.dim, *dims = mat->stencil.dims + 1, tmp;
1871:   PetscInt *starts = mat->stencil.starts, *dxm = (PetscInt *)idxm, *dxn = (PetscInt *)idxn, sdim = dim - (1 - (PetscInt)mat->stencil.noc);

1873:   PetscFunctionBegin;
1874:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
1877:   PetscAssertPointer(idxm, 3);
1878:   PetscAssertPointer(idxn, 5);
1879:   PetscAssertPointer(v, 6);

1881:   if ((m + n) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
1882:     jdxm = buf;
1883:     jdxn = buf + m;
1884:   } else {
1885:     PetscCall(PetscMalloc2(m, &bufm, n, &bufn));
1886:     jdxm = bufm;
1887:     jdxn = bufn;
1888:   }
1889:   for (i = 0; i < m; i++) {
1890:     for (j = 0; j < 3 - sdim; j++) dxm++;
1891:     tmp = *dxm++ - starts[0];
1892:     for (j = 0; j < sdim - 1; j++) {
1893:       if ((*dxm++ - starts[j + 1]) < 0 || tmp < 0) tmp = -1;
1894:       else tmp = tmp * dims[j] + *(dxm - 1) - starts[j + 1];
1895:     }
1896:     dxm++;
1897:     jdxm[i] = tmp;
1898:   }
1899:   for (i = 0; i < n; i++) {
1900:     for (j = 0; j < 3 - sdim; j++) dxn++;
1901:     tmp = *dxn++ - starts[0];
1902:     for (j = 0; j < sdim - 1; j++) {
1903:       if ((*dxn++ - starts[j + 1]) < 0 || tmp < 0) tmp = -1;
1904:       else tmp = tmp * dims[j] + *(dxn - 1) - starts[j + 1];
1905:     }
1906:     dxn++;
1907:     jdxn[i] = tmp;
1908:   }
1909:   PetscCall(MatSetValuesBlockedLocal(mat, m, jdxm, n, jdxn, v, addv));
1910:   PetscCall(PetscFree2(bufm, bufn));
1911:   PetscFunctionReturn(PETSC_SUCCESS);
1912: }

1914: /*@
1915:   MatSetStencil - Sets the grid information for setting values into a matrix via
1916:   `MatSetValuesStencil()`

1918:   Not Collective

1920:   Input Parameters:
1921: + mat    - the matrix
1922: . dim    - dimension of the grid 1, 2, or 3
1923: . dims   - number of grid points in x, y, and z direction, including ghost points on your processor
1924: . starts - starting point of ghost nodes on your processor in x, y, and z direction
1925: - dof    - number of degrees of freedom per node

1927:   Level: beginner

1929:   Notes:
1930:   Inspired by the structured grid interface to the HYPRE package
1931:   (www.llnl.gov/CASC/hyper)

1933:   For matrices generated with `DMCreateMatrix()` this routine is automatically called and so not needed by the
1934:   user.

1936: .seealso: [](ch_matrices), `Mat`, `MatStencil`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`
1937:           `MatSetValues()`, `MatSetValuesBlockedStencil()`, `MatSetValuesStencil()`
1938: @*/
1939: PetscErrorCode MatSetStencil(Mat mat, PetscInt dim, const PetscInt dims[], const PetscInt starts[], PetscInt dof)
1940: {
1941:   PetscFunctionBegin;
1943:   PetscAssertPointer(dims, 3);
1944:   PetscAssertPointer(starts, 4);

1946:   mat->stencil.dim = dim + (dof > 1);
1947:   for (PetscInt i = 0; i < dim; i++) {
1948:     mat->stencil.dims[i]   = dims[dim - i - 1]; /* copy the values in backwards */
1949:     mat->stencil.starts[i] = starts[dim - i - 1];
1950:   }
1951:   mat->stencil.dims[dim]   = dof;
1952:   mat->stencil.starts[dim] = 0;
1953:   mat->stencil.noc         = (PetscBool)(dof == 1);
1954:   PetscFunctionReturn(PETSC_SUCCESS);
1955: }

1957: /*@
1958:   MatSetValuesBlocked - Inserts or adds a block of values into a matrix.

1960:   Not Collective

1962:   Input Parameters:
1963: + mat  - the matrix
1964: . v    - a logically two-dimensional array of values
1965: . m    - the number of block rows
1966: . idxm - the global block indices
1967: . n    - the number of block columns
1968: . idxn - the global block indices
1969: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` replaces existing entries with new values

1971:   Level: intermediate

1973:   Notes:
1974:   If you create the matrix yourself (that is not with a call to `DMCreateMatrix()`) then you MUST call
1975:   MatXXXXSetPreallocation() or `MatSetUp()` before using this routine.

1977:   The `m` and `n` count the NUMBER of blocks in the row direction and column direction,
1978:   NOT the total number of rows/columns; for example, if the block size is 2 and
1979:   you are passing in values for rows 2,3,4,5  then `m` would be 2 (not 4).
1980:   The values in `idxm` would be 1 2; that is the first index for each block divided by
1981:   the block size.

1983:   You must call `MatSetBlockSize()` when constructing this matrix (before
1984:   preallocating it).

1986:   By default the values, `v`, are row-oriented, so the layout of
1987:   `v` is the same as for `MatSetValues()`. See `MatSetOption()` for other options.

1989:   Calls to `MatSetValuesBlocked()` with the `INSERT_VALUES` and `ADD_VALUES`
1990:   options cannot be mixed without intervening calls to the assembly
1991:   routines.

1993:   `MatSetValuesBlocked()` uses 0-based row and column numbers in Fortran
1994:   as well as in C.

1996:   Negative indices may be passed in `idxm` and `idxn`, these rows and columns are
1997:   simply ignored. This allows easily inserting element stiffness matrices
1998:   with homogeneous Dirichlet boundary conditions that you don't want represented
1999:   in the matrix.

2001:   Each time an entry is set within a sparse matrix via `MatSetValues()`,
2002:   internal searching must be done to determine where to place the
2003:   data in the matrix storage space.  By instead inserting blocks of
2004:   entries via `MatSetValuesBlocked()`, the overhead of matrix assembly is
2005:   reduced.

2007:   Example:
2008: .vb
2009:    Suppose m=n=2 and block size(bs) = 2 The array is

2011:    1  2  | 3  4
2012:    5  6  | 7  8
2013:    - - - | - - -
2014:    9  10 | 11 12
2015:    13 14 | 15 16

2017:    v[] should be passed in like
2018:    v[] = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]

2020:   If you are not using row-oriented storage of v (that is you called MatSetOption(mat,MAT_ROW_ORIENTED,PETSC_FALSE)) then
2021:    v[] = [1,5,9,13,2,6,10,14,3,7,11,15,4,8,12,16]
2022: .ve

2024:   Fortran Notes:
2025:   If any of `idmx`, `idxn`, and `v` are scalars pass them using, for example,
2026: .vb
2027:   MatSetValuesBlocked(mat, one, [idxm], one, [idxn], [v], INSERT_VALUES)
2028: .ve

2030:   If `v` is a two-dimensional array use `reshape()` to pass it as a one dimensional array

2032: .seealso: [](ch_matrices), `Mat`, `MatSetBlockSize()`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValues()`, `MatSetValuesBlockedLocal()`
2033: @*/
2034: PetscErrorCode MatSetValuesBlocked(Mat mat, PetscInt m, const PetscInt idxm[], PetscInt n, const PetscInt idxn[], const PetscScalar v[], InsertMode addv)
2035: {
2036:   PetscFunctionBeginHot;
2039:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
2040:   PetscAssertPointer(idxm, 3);
2041:   PetscAssertPointer(idxn, 5);
2042:   MatCheckPreallocated(mat, 1);
2043:   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
2044:   else PetscCheck(mat->insertmode == addv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add values and insert values");
2045:   if (PetscDefined(USE_DEBUG)) {
2046:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2047:     PetscCheck(mat->ops->setvaluesblocked || mat->ops->setvalues, PETSC_COMM_SELF, PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2048:   }
2049:   if (PetscDefined(USE_DEBUG)) {
2050:     PetscInt rbs, cbs, M, N, i;
2051:     PetscCall(MatGetBlockSizes(mat, &rbs, &cbs));
2052:     PetscCall(MatGetSize(mat, &M, &N));
2053:     for (i = 0; i < m; i++) PetscCheck(idxm[i] * rbs < M, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Row block %" PetscInt_FMT " contains an index %" PetscInt_FMT "*%" PetscInt_FMT " greater than row length %" PetscInt_FMT, i, idxm[i], rbs, M);
2054:     for (i = 0; i < n; i++)
2055:       PetscCheck(idxn[i] * cbs < N, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Column block %" PetscInt_FMT " contains an index %" PetscInt_FMT "*%" PetscInt_FMT " greater than column length %" PetscInt_FMT, i, idxn[i], cbs, N);
2056:   }
2057:   if (mat->assembled) {
2058:     mat->was_assembled = PETSC_TRUE;
2059:     mat->assembled     = PETSC_FALSE;
2060:   }
2061:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
2062:   if (mat->ops->setvaluesblocked) {
2063:     PetscUseTypeMethod(mat, setvaluesblocked, m, idxm, n, idxn, v, addv);
2064:   } else {
2065:     PetscInt buf[8192], *bufr = NULL, *bufc = NULL, *iidxm, *iidxn;
2066:     PetscInt i, j, bs, cbs;

2068:     PetscCall(MatGetBlockSizes(mat, &bs, &cbs));
2069:     if ((m * bs + n * cbs) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
2070:       iidxm = buf;
2071:       iidxn = buf + m * bs;
2072:     } else {
2073:       PetscCall(PetscMalloc2(m * bs, &bufr, n * cbs, &bufc));
2074:       iidxm = bufr;
2075:       iidxn = bufc;
2076:     }
2077:     for (i = 0; i < m; i++) {
2078:       for (j = 0; j < bs; j++) iidxm[i * bs + j] = bs * idxm[i] + j;
2079:     }
2080:     if (m != n || bs != cbs || idxm != idxn) {
2081:       for (i = 0; i < n; i++) {
2082:         for (j = 0; j < cbs; j++) iidxn[i * cbs + j] = cbs * idxn[i] + j;
2083:       }
2084:     } else iidxn = iidxm;
2085:     PetscCall(MatSetValues(mat, m * bs, iidxm, n * cbs, iidxn, v, addv));
2086:     PetscCall(PetscFree2(bufr, bufc));
2087:   }
2088:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
2089:   PetscFunctionReturn(PETSC_SUCCESS);
2090: }

2092: /*@
2093:   MatGetValues - Gets a block of local values from a matrix.

2095:   Not Collective; can only return values that are owned by the give process

2097:   Input Parameters:
2098: + mat  - the matrix
2099: . v    - a logically two-dimensional array for storing the values
2100: . m    - the number of rows
2101: . idxm - the  global indices of the rows
2102: . n    - the number of columns
2103: - idxn - the global indices of the columns

2105:   Level: advanced

2107:   Notes:
2108:   The user must allocate space (m*n `PetscScalar`s) for the values, `v`.
2109:   The values, `v`, are then returned in a row-oriented format,
2110:   analogous to that used by default in `MatSetValues()`.

2112:   `MatGetValues()` uses 0-based row and column numbers in
2113:   Fortran as well as in C.

2115:   `MatGetValues()` requires that the matrix has been assembled
2116:   with `MatAssemblyBegin()`/`MatAssemblyEnd()`.  Thus, calls to
2117:   `MatSetValues()` and `MatGetValues()` CANNOT be made in succession
2118:   without intermediate matrix assembly.

2120:   Negative row or column indices will be ignored and those locations in `v` will be
2121:   left unchanged.

2123:   For the standard row-based matrix formats, `idxm` can only contain rows owned by the requesting MPI process.
2124:   That is, rows with global index greater than or equal to rstart and less than rend where rstart and rend are obtainable
2125:   from `MatGetOwnershipRange`(mat,&rstart,&rend).

2127: .seealso: [](ch_matrices), `Mat`, `MatGetRow()`, `MatCreateSubMatrices()`, `MatSetValues()`, `MatGetOwnershipRange()`, `MatGetValuesLocal()`, `MatGetValue()`
2128: @*/
2129: PetscErrorCode MatGetValues(Mat mat, PetscInt m, const PetscInt idxm[], PetscInt n, const PetscInt idxn[], PetscScalar v[])
2130: {
2131:   PetscFunctionBegin;
2134:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS);
2135:   PetscAssertPointer(idxm, 3);
2136:   PetscAssertPointer(idxn, 5);
2137:   PetscAssertPointer(v, 6);
2138:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2139:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2140:   MatCheckPreallocated(mat, 1);

2142:   PetscCall(PetscLogEventBegin(MAT_GetValues, mat, 0, 0, 0));
2143:   PetscUseTypeMethod(mat, getvalues, m, idxm, n, idxn, v);
2144:   PetscCall(PetscLogEventEnd(MAT_GetValues, mat, 0, 0, 0));
2145:   PetscFunctionReturn(PETSC_SUCCESS);
2146: }

2148: /*@
2149:   MatGetValuesLocal - retrieves values from certain locations in a matrix using the local numbering of the indices
2150:   defined previously by `MatSetLocalToGlobalMapping()`

2152:   Not Collective

2154:   Input Parameters:
2155: + mat  - the matrix
2156: . nrow - number of rows
2157: . irow - the row local indices
2158: . ncol - number of columns
2159: - icol - the column local indices

2161:   Output Parameter:
2162: . y - a logically two-dimensional array of values

2164:   Level: advanced

2166:   Notes:
2167:   If you create the matrix yourself (that is not with a call to `DMCreateMatrix()`) then you MUST call `MatSetLocalToGlobalMapping()` before using this routine.

2169:   This routine can only return values that are owned by the requesting MPI process. That is, for standard matrix formats, rows that, in the global numbering,
2170:   are greater than or equal to rstart and less than rend where rstart and rend are obtainable from `MatGetOwnershipRange`(mat,&rstart,&rend). One can
2171:   determine if the resulting global row associated with the local row r is owned by the requesting MPI process by applying the `ISLocalToGlobalMapping` set
2172:   with `MatSetLocalToGlobalMapping()`.

2174:   Developer Note:
2175:   This is labelled with C so does not automatically generate Fortran stubs and interfaces
2176:   because it requires multiple Fortran interfaces depending on which arguments are scalar or arrays.

2178: .seealso: [](ch_matrices), `Mat`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValues()`, `MatSetLocalToGlobalMapping()`,
2179:           `MatSetValuesLocal()`, `MatGetValues()`
2180: @*/
2181: PetscErrorCode MatGetValuesLocal(Mat mat, PetscInt nrow, const PetscInt irow[], PetscInt ncol, const PetscInt icol[], PetscScalar y[])
2182: {
2183:   PetscFunctionBeginHot;
2186:   MatCheckPreallocated(mat, 1);
2187:   if (!nrow || !ncol) PetscFunctionReturn(PETSC_SUCCESS); /* no values to retrieve */
2188:   PetscAssertPointer(irow, 3);
2189:   PetscAssertPointer(icol, 5);
2190:   if (PetscDefined(USE_DEBUG)) {
2191:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2192:     PetscCheck(mat->ops->getvalueslocal || mat->ops->getvalues, PETSC_COMM_SELF, PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2193:   }
2194:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2195:   PetscCall(PetscLogEventBegin(MAT_GetValues, mat, 0, 0, 0));
2196:   if (mat->ops->getvalueslocal) PetscUseTypeMethod(mat, getvalueslocal, nrow, irow, ncol, icol, y);
2197:   else {
2198:     PetscInt buf[8192], *bufr = NULL, *bufc = NULL, *irowm, *icolm;
2199:     if ((nrow + ncol) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
2200:       irowm = buf;
2201:       icolm = buf + nrow;
2202:     } else {
2203:       PetscCall(PetscMalloc2(nrow, &bufr, ncol, &bufc));
2204:       irowm = bufr;
2205:       icolm = bufc;
2206:     }
2207:     PetscCheck(mat->rmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "MatGetValuesLocal() cannot proceed without local-to-global row mapping (See MatSetLocalToGlobalMapping()).");
2208:     PetscCheck(mat->cmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "MatGetValuesLocal() cannot proceed without local-to-global column mapping (See MatSetLocalToGlobalMapping()).");
2209:     PetscCall(ISLocalToGlobalMappingApply(mat->rmap->mapping, nrow, irow, irowm));
2210:     PetscCall(ISLocalToGlobalMappingApply(mat->cmap->mapping, ncol, icol, icolm));
2211:     PetscCall(MatGetValues(mat, nrow, irowm, ncol, icolm, y));
2212:     PetscCall(PetscFree2(bufr, bufc));
2213:   }
2214:   PetscCall(PetscLogEventEnd(MAT_GetValues, mat, 0, 0, 0));
2215:   PetscFunctionReturn(PETSC_SUCCESS);
2216: }

2218: /*@
2219:   MatSetValuesBatch - Adds (`ADD_VALUES`) many blocks of values into a matrix at once. The blocks must all be square and
2220:   the same size. Currently, this can only be called once and creates the given matrix.

2222:   Not Collective

2224:   Input Parameters:
2225: + mat  - the matrix
2226: . nb   - the number of blocks
2227: . bs   - the number of rows (and columns) in each block
2228: . rows - a concatenation of the rows for each block
2229: - v    - a concatenation of logically two-dimensional arrays of values

2231:   Level: advanced

2233:   Notes:
2234:   `MatSetPreallocationCOO()` and `MatSetValuesCOO()` may be a better way to provide the values

2236:   In the future, we will extend this routine to handle rectangular blocks, and to allow multiple calls for a given matrix.

2238: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
2239:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`, `MatSetValues()`, `MatSetPreallocationCOO()`, `MatSetValuesCOO()`
2240: @*/
2241: PetscErrorCode MatSetValuesBatch(Mat mat, PetscInt nb, PetscInt bs, PetscInt rows[], const PetscScalar v[])
2242: {
2243:   PetscFunctionBegin;
2246:   PetscAssertPointer(rows, 4);
2247:   PetscAssertPointer(v, 5);
2248:   PetscAssert(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");

2250:   PetscCall(PetscLogEventBegin(MAT_SetValuesBatch, mat, 0, 0, 0));
2251:   if (mat->ops->setvaluesbatch) PetscUseTypeMethod(mat, setvaluesbatch, nb, bs, rows, v);
2252:   else {
2253:     for (PetscInt b = 0; b < nb; ++b) PetscCall(MatSetValues(mat, bs, &rows[b * bs], bs, &rows[b * bs], &v[b * bs * bs], ADD_VALUES));
2254:   }
2255:   PetscCall(PetscLogEventEnd(MAT_SetValuesBatch, mat, 0, 0, 0));
2256:   PetscFunctionReturn(PETSC_SUCCESS);
2257: }

2259: /*@
2260:   MatSetLocalToGlobalMapping - Sets a local-to-global numbering for use by
2261:   the routine `MatSetValuesLocal()` to allow users to insert matrix entries
2262:   using a local (per-processor) numbering.

2264:   Not Collective

2266:   Input Parameters:
2267: + x        - the matrix
2268: . rmapping - row mapping created with `ISLocalToGlobalMappingCreate()` or `ISLocalToGlobalMappingCreateIS()`
2269: - cmapping - column mapping

2271:   Level: intermediate

2273:   Note:
2274:   If the matrix is obtained with `DMCreateMatrix()` then this may already have been called on the matrix

2276: .seealso: [](ch_matrices), `Mat`, `DM`, `DMCreateMatrix()`, `MatGetLocalToGlobalMapping()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValues()`, `MatSetValuesLocal()`, `MatGetValuesLocal()`
2277: @*/
2278: PetscErrorCode MatSetLocalToGlobalMapping(Mat x, ISLocalToGlobalMapping rmapping, ISLocalToGlobalMapping cmapping)
2279: {
2280:   PetscFunctionBegin;
2285:   if (x->ops->setlocaltoglobalmapping) PetscUseTypeMethod(x, setlocaltoglobalmapping, rmapping, cmapping);
2286:   else {
2287:     PetscCall(PetscLayoutSetISLocalToGlobalMapping(x->rmap, rmapping));
2288:     PetscCall(PetscLayoutSetISLocalToGlobalMapping(x->cmap, cmapping));
2289:   }
2290:   PetscFunctionReturn(PETSC_SUCCESS);
2291: }

2293: /*@
2294:   MatGetLocalToGlobalMapping - Gets the local-to-global numbering set by `MatSetLocalToGlobalMapping()`

2296:   Not Collective

2298:   Input Parameter:
2299: . A - the matrix

2301:   Output Parameters:
2302: + rmapping - row mapping
2303: - cmapping - column mapping

2305:   Level: advanced

2307: .seealso: [](ch_matrices), `Mat`, `MatSetLocalToGlobalMapping()`, `MatSetValuesLocal()`
2308: @*/
2309: PetscErrorCode MatGetLocalToGlobalMapping(Mat A, ISLocalToGlobalMapping *rmapping, ISLocalToGlobalMapping *cmapping)
2310: {
2311:   PetscFunctionBegin;
2314:   if (rmapping) {
2315:     PetscAssertPointer(rmapping, 2);
2316:     *rmapping = A->rmap->mapping;
2317:   }
2318:   if (cmapping) {
2319:     PetscAssertPointer(cmapping, 3);
2320:     *cmapping = A->cmap->mapping;
2321:   }
2322:   PetscFunctionReturn(PETSC_SUCCESS);
2323: }

2325: /*@
2326:   MatSetLayouts - Sets the `PetscLayout` objects for rows and columns of a matrix

2328:   Logically Collective

2330:   Input Parameters:
2331: + A    - the matrix
2332: . rmap - row layout
2333: - cmap - column layout

2335:   Level: advanced

2337:   Note:
2338:   The `PetscLayout` objects are usually created automatically for the matrix so this routine rarely needs to be called.

2340: .seealso: [](ch_matrices), `Mat`, `PetscLayout`, `MatCreateVecs()`, `MatGetLocalToGlobalMapping()`, `MatGetLayouts()`
2341: @*/
2342: PetscErrorCode MatSetLayouts(Mat A, PetscLayout rmap, PetscLayout cmap)
2343: {
2344:   PetscFunctionBegin;
2346:   PetscCall(PetscLayoutReference(rmap, &A->rmap));
2347:   PetscCall(PetscLayoutReference(cmap, &A->cmap));
2348:   PetscFunctionReturn(PETSC_SUCCESS);
2349: }

2351: /*@
2352:   MatGetLayouts - Gets the `PetscLayout` objects for rows and columns

2354:   Not Collective

2356:   Input Parameter:
2357: . A - the matrix

2359:   Output Parameters:
2360: + rmap - row layout
2361: - cmap - column layout

2363:   Level: advanced

2365: .seealso: [](ch_matrices), `Mat`, [Matrix Layouts](sec_matlayout), `PetscLayout`, `MatCreateVecs()`, `MatGetLocalToGlobalMapping()`, `MatSetLayouts()`
2366: @*/
2367: PetscErrorCode MatGetLayouts(Mat A, PetscLayout *rmap, PetscLayout *cmap)
2368: {
2369:   PetscFunctionBegin;
2372:   if (rmap) {
2373:     PetscAssertPointer(rmap, 2);
2374:     *rmap = A->rmap;
2375:   }
2376:   if (cmap) {
2377:     PetscAssertPointer(cmap, 3);
2378:     *cmap = A->cmap;
2379:   }
2380:   PetscFunctionReturn(PETSC_SUCCESS);
2381: }

2383: /*@
2384:   MatSetValuesLocal - Inserts or adds values into certain locations of a matrix,
2385:   using a local numbering of the rows and columns.

2387:   Not Collective

2389:   Input Parameters:
2390: + mat  - the matrix
2391: . nrow - number of rows
2392: . irow - the row local indices
2393: . ncol - number of columns
2394: . icol - the column local indices
2395: . y    - a logically two-dimensional array of values
2396: - addv - either `INSERT_VALUES` to add values to any existing entries, or `INSERT_VALUES` to replace existing entries with new values

2398:   Level: intermediate

2400:   Notes:
2401:   If you create the matrix yourself (that is not with a call to `DMCreateMatrix()`) then you MUST call `MatSetLocalToGlobalMapping()` before using this routine

2403:   Calls to `MatSetValuesLocal()` with the `INSERT_VALUES` and `ADD_VALUES`
2404:   options cannot be mixed without intervening calls to the assembly
2405:   routines.

2407:   These values may be cached, so `MatAssemblyBegin()` and `MatAssemblyEnd()`
2408:   MUST be called after all calls to `MatSetValuesLocal()` have been completed.

2410:   Fortran Notes:
2411:   If any of `irow`, `icol`, and `y` are scalars pass them using, for example,
2412: .vb
2413:   MatSetValuesLocal(mat, one, [irow], one, [icol], [y], INSERT_VALUES)
2414: .ve

2416:   If `y` is a two-dimensional array use `reshape()` to pass it as a one dimensional array

2418:   Developer Note:
2419:   This is labeled with C so does not automatically generate Fortran stubs and interfaces
2420:   because it requires multiple Fortran interfaces depending on which arguments are scalar or arrays.

2422: .seealso: [](ch_matrices), `Mat`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValues()`, `MatSetLocalToGlobalMapping()`,
2423:           `MatGetValuesLocal()`
2424: @*/
2425: PetscErrorCode MatSetValuesLocal(Mat mat, PetscInt nrow, const PetscInt irow[], PetscInt ncol, const PetscInt icol[], const PetscScalar y[], InsertMode addv)
2426: {
2427:   PetscFunctionBeginHot;
2430:   MatCheckPreallocated(mat, 1);
2431:   if (!nrow || !ncol) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
2432:   PetscAssertPointer(irow, 3);
2433:   PetscAssertPointer(icol, 5);
2434:   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
2435:   else PetscCheck(mat->insertmode == addv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add values and insert values");
2436:   if (PetscDefined(USE_DEBUG)) {
2437:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2438:     PetscCheck(mat->ops->setvalueslocal || mat->ops->setvalues, PETSC_COMM_SELF, PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2439:   }

2441:   if (mat->assembled) {
2442:     mat->was_assembled = PETSC_TRUE;
2443:     mat->assembled     = PETSC_FALSE;
2444:   }
2445:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
2446:   if (mat->ops->setvalueslocal) PetscUseTypeMethod(mat, setvalueslocal, nrow, irow, ncol, icol, y, addv);
2447:   else {
2448:     PetscInt        buf[8192], *bufr = NULL, *bufc = NULL;
2449:     const PetscInt *irowm, *icolm;

2451:     if ((!mat->rmap->mapping && !mat->cmap->mapping) || (nrow + ncol) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
2452:       bufr  = buf;
2453:       bufc  = buf + nrow;
2454:       irowm = bufr;
2455:       icolm = bufc;
2456:     } else {
2457:       PetscCall(PetscMalloc2(nrow, &bufr, ncol, &bufc));
2458:       irowm = bufr;
2459:       icolm = bufc;
2460:     }
2461:     if (mat->rmap->mapping) PetscCall(ISLocalToGlobalMappingApply(mat->rmap->mapping, nrow, irow, bufr));
2462:     else irowm = irow;
2463:     if (mat->cmap->mapping) {
2464:       if (mat->cmap->mapping != mat->rmap->mapping || ncol != nrow || icol != irow) {
2465:         PetscCall(ISLocalToGlobalMappingApply(mat->cmap->mapping, ncol, icol, bufc));
2466:       } else icolm = irowm;
2467:     } else icolm = icol;
2468:     PetscCall(MatSetValues(mat, nrow, irowm, ncol, icolm, y, addv));
2469:     if (bufr != buf) PetscCall(PetscFree2(bufr, bufc));
2470:   }
2471:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
2472:   PetscFunctionReturn(PETSC_SUCCESS);
2473: }

2475: /*@
2476:   MatSetValuesBlockedLocal - Inserts or adds values into certain locations of a matrix,
2477:   using a local ordering of the nodes a block at a time.

2479:   Not Collective

2481:   Input Parameters:
2482: + mat  - the matrix
2483: . nrow - number of rows
2484: . irow - the row local indices
2485: . ncol - number of columns
2486: . icol - the column local indices
2487: . y    - a logically two-dimensional array of values
2488: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` to replace existing entries with new values

2490:   Level: intermediate

2492:   Notes:
2493:   If you create the matrix yourself (that is not with a call to `DMCreateMatrix()`) then you MUST call `MatSetBlockSize()` and `MatSetLocalToGlobalMapping()`
2494:   before using this routineBefore calling `MatSetValuesLocal()`, the user must first set the

2496:   Calls to `MatSetValuesBlockedLocal()` with the `INSERT_VALUES` and `ADD_VALUES`
2497:   options cannot be mixed without intervening calls to the assembly
2498:   routines.

2500:   These values may be cached, so `MatAssemblyBegin()` and `MatAssemblyEnd()`
2501:   MUST be called after all calls to `MatSetValuesBlockedLocal()` have been completed.

2503:   Fortran Notes:
2504:   If any of `irow`, `icol`, and `y` are scalars pass them using, for example,
2505: .vb
2506:   MatSetValuesBlockedLocal(mat, one, [irow], one, [icol], [y], INSERT_VALUES)
2507: .ve

2509:   If `y` is a two-dimensional array use `reshape()` to pass it as a one dimensional array

2511:   Developer Note:
2512:   This is labeled with C so does not automatically generate Fortran stubs and interfaces
2513:   because it requires multiple Fortran interfaces depending on which arguments are scalar or arrays.

2515: .seealso: [](ch_matrices), `Mat`, `MatSetBlockSize()`, `MatSetLocalToGlobalMapping()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`,
2516:           `MatSetValuesLocal()`, `MatSetValuesBlocked()`
2517: @*/
2518: PetscErrorCode MatSetValuesBlockedLocal(Mat mat, PetscInt nrow, const PetscInt irow[], PetscInt ncol, const PetscInt icol[], const PetscScalar y[], InsertMode addv)
2519: {
2520:   PetscFunctionBeginHot;
2523:   MatCheckPreallocated(mat, 1);
2524:   if (!nrow || !ncol) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
2525:   PetscAssertPointer(irow, 3);
2526:   PetscAssertPointer(icol, 5);
2527:   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
2528:   else PetscCheck(mat->insertmode == addv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add values and insert values");
2529:   if (PetscDefined(USE_DEBUG)) {
2530:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2531:     PetscCheck(mat->ops->setvaluesblockedlocal || mat->ops->setvaluesblocked || mat->ops->setvalueslocal || mat->ops->setvalues, PETSC_COMM_SELF, PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2532:   }

2534:   if (mat->assembled) {
2535:     mat->was_assembled = PETSC_TRUE;
2536:     mat->assembled     = PETSC_FALSE;
2537:   }
2538:   if (PetscUnlikelyDebug(mat->rmap->mapping)) { /* Condition on the mapping existing, because MatSetValuesBlockedLocal_IS does not require it to be set. */
2539:     PetscInt irbs, rbs;
2540:     PetscCall(MatGetBlockSizes(mat, &rbs, NULL));
2541:     PetscCall(ISLocalToGlobalMappingGetBlockSize(mat->rmap->mapping, &irbs));
2542:     PetscCheck(rbs == irbs, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Different row block sizes! mat %" PetscInt_FMT ", row l2g map %" PetscInt_FMT, rbs, irbs);
2543:   }
2544:   if (PetscUnlikelyDebug(mat->cmap->mapping)) {
2545:     PetscInt icbs, cbs;
2546:     PetscCall(MatGetBlockSizes(mat, NULL, &cbs));
2547:     PetscCall(ISLocalToGlobalMappingGetBlockSize(mat->cmap->mapping, &icbs));
2548:     PetscCheck(cbs == icbs, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Different col block sizes! mat %" PetscInt_FMT ", col l2g map %" PetscInt_FMT, cbs, icbs);
2549:   }
2550:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
2551:   if (mat->ops->setvaluesblockedlocal) PetscUseTypeMethod(mat, setvaluesblockedlocal, nrow, irow, ncol, icol, y, addv);
2552:   else {
2553:     PetscInt        buf[8192], *bufr = NULL, *bufc = NULL;
2554:     const PetscInt *irowm, *icolm;

2556:     if ((!mat->rmap->mapping && !mat->cmap->mapping) || (nrow + ncol) <= ((PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf))) {
2557:       bufr  = buf;
2558:       bufc  = buf + nrow;
2559:       irowm = bufr;
2560:       icolm = bufc;
2561:     } else {
2562:       PetscCall(PetscMalloc2(nrow, &bufr, ncol, &bufc));
2563:       irowm = bufr;
2564:       icolm = bufc;
2565:     }
2566:     if (mat->rmap->mapping) PetscCall(ISLocalToGlobalMappingApplyBlock(mat->rmap->mapping, nrow, irow, bufr));
2567:     else irowm = irow;
2568:     if (mat->cmap->mapping) {
2569:       if (mat->cmap->mapping != mat->rmap->mapping || ncol != nrow || icol != irow) {
2570:         PetscCall(ISLocalToGlobalMappingApplyBlock(mat->cmap->mapping, ncol, icol, bufc));
2571:       } else icolm = irowm;
2572:     } else icolm = icol;
2573:     PetscCall(MatSetValuesBlocked(mat, nrow, irowm, ncol, icolm, y, addv));
2574:     if (bufr != buf) PetscCall(PetscFree2(bufr, bufc));
2575:   }
2576:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
2577:   PetscFunctionReturn(PETSC_SUCCESS);
2578: }

2580: /*@
2581:   MatMultDiagonalBlock - Computes the matrix-vector product, $y = Dx$. Where `D` is defined by the inode or block structure of the diagonal

2583:   Collective

2585:   Input Parameters:
2586: + mat - the matrix
2587: - x   - the vector to be multiplied

2589:   Output Parameter:
2590: . y - the result

2592:   Level: developer

2594:   Note:
2595:   The vectors `x` and `y` cannot be the same.  I.e., one cannot
2596:   call `MatMultDiagonalBlock`(A,y,y).

2598: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatMultTranspose()`, `MatMultAdd()`, `MatMultTransposeAdd()`
2599: @*/
2600: PetscErrorCode MatMultDiagonalBlock(Mat mat, Vec x, Vec y)
2601: {
2602:   PetscFunctionBegin;

2608:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2609:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2610:   PetscCheck(x != y, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "x and y must be different vectors");
2611:   MatCheckPreallocated(mat, 1);

2613:   PetscUseTypeMethod(mat, multdiagonalblock, x, y);
2614:   PetscCall(PetscObjectStateIncrease((PetscObject)y));
2615:   PetscFunctionReturn(PETSC_SUCCESS);
2616: }

2618: /*@
2619:   MatMult - Computes the matrix-vector product, $y = Ax$.

2621:   Neighbor-wise Collective

2623:   Input Parameters:
2624: + mat - the matrix
2625: - x   - the vector to be multiplied

2627:   Output Parameter:
2628: . y - the result

2630:   Level: beginner

2632:   Note:
2633:   The vectors `x` and `y` cannot be the same.  I.e., one cannot
2634:   call `MatMult`(A,y,y).

2636: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMultAdd()`, `MatMultTransposeAdd()`
2637: @*/
2638: PetscErrorCode MatMult(Mat mat, Vec x, Vec y)
2639: {
2640:   PetscFunctionBegin;
2644:   VecCheckAssembled(x);
2646:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2647:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2648:   PetscCheck(x != y, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "x and y must be different vectors");
2649:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
2650:   PetscCheck(mat->rmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, y->map->N);
2651:   PetscCheck(mat->cmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->n, x->map->n);
2652:   PetscCheck(mat->rmap->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, y->map->n);
2653:   PetscCall(VecSetErrorIfLocked(y, 3));
2654:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2655:   MatCheckPreallocated(mat, 1);

2657:   PetscCall(VecLockReadPush(x));
2658:   PetscCall(PetscLogEventBegin(MAT_Mult, mat, x, y, 0));
2659:   PetscUseTypeMethod(mat, mult, x, y);
2660:   PetscCall(PetscLogEventEnd(MAT_Mult, mat, x, y, 0));
2661:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(y, 3, PETSC_FALSE));
2662:   PetscCall(VecLockReadPop(x));
2663:   PetscFunctionReturn(PETSC_SUCCESS);
2664: }

2666: /*@
2667:   MatMultTranspose - Computes matrix transpose times a vector $y = A^T * x$.

2669:   Neighbor-wise Collective

2671:   Input Parameters:
2672: + mat - the matrix
2673: - x   - the vector to be multiplied

2675:   Output Parameter:
2676: . y - the result

2678:   Level: beginner

2680:   Notes:
2681:   The vectors `x` and `y` cannot be the same.  I.e., one cannot
2682:   call `MatMultTranspose`(A,y,y).

2684:   For complex numbers this does NOT compute the Hermitian (complex conjugate) transpose multiple,
2685:   use `MatMultHermitianTranspose()`

2687: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatMultAdd()`, `MatMultTransposeAdd()`, `MatMultHermitianTranspose()`, `MatTranspose()`
2688: @*/
2689: PetscErrorCode MatMultTranspose(Mat mat, Vec x, Vec y)
2690: {
2691:   PetscErrorCode (*op)(Mat, Vec, Vec) = NULL;

2693:   PetscFunctionBegin;
2697:   VecCheckAssembled(x);

2700:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2701:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2702:   PetscCheck(x != y, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "x and y must be different vectors");
2703:   PetscCheck(mat->cmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, y->map->N);
2704:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
2705:   PetscCheck(mat->cmap->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->n, y->map->n);
2706:   PetscCheck(mat->rmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, x->map->n);
2707:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2708:   MatCheckPreallocated(mat, 1);

2710:   if (!mat->ops->multtranspose) {
2711:     if (mat->symmetric == PETSC_BOOL3_TRUE && mat->ops->mult) op = mat->ops->mult;
2712:     PetscCheck(op, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Matrix type %s does not have a multiply transpose defined or is symmetric and does not have a multiply defined", ((PetscObject)mat)->type_name);
2713:   } else op = mat->ops->multtranspose;
2714:   PetscCall(PetscLogEventBegin(MAT_MultTranspose, mat, x, y, 0));
2715:   PetscCall(VecLockReadPush(x));
2716:   PetscCall((*op)(mat, x, y));
2717:   PetscCall(VecLockReadPop(x));
2718:   PetscCall(PetscLogEventEnd(MAT_MultTranspose, mat, x, y, 0));
2719:   PetscCall(PetscObjectStateIncrease((PetscObject)y));
2720:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(y, 3, PETSC_FALSE));
2721:   PetscFunctionReturn(PETSC_SUCCESS);
2722: }

2724: /*@
2725:   MatMultHermitianTranspose - Computes matrix Hermitian-transpose times a vector $y = A^H * x$.

2727:   Neighbor-wise Collective

2729:   Input Parameters:
2730: + mat - the matrix
2731: - x   - the vector to be multiplied

2733:   Output Parameter:
2734: . y - the result

2736:   Level: beginner

2738:   Notes:
2739:   The vectors `x` and `y` cannot be the same.  I.e., one cannot
2740:   call `MatMultHermitianTranspose`(A,y,y).

2742:   Also called the conjugate transpose, complex conjugate transpose, or adjoint.

2744:   For real numbers `MatMultTranspose()` and `MatMultHermitianTranspose()` are identical.

2746: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatMultAdd()`, `MatMultHermitianTransposeAdd()`, `MatMultTranspose()`
2747: @*/
2748: PetscErrorCode MatMultHermitianTranspose(Mat mat, Vec x, Vec y)
2749: {
2750:   PetscFunctionBegin;

2756:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2757:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2758:   PetscCheck(x != y, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "x and y must be different vectors");
2759:   PetscCheck(mat->cmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, y->map->N);
2760:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
2761:   PetscCheck(mat->cmap->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->n, y->map->n);
2762:   PetscCheck(mat->rmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, x->map->n);
2763:   MatCheckPreallocated(mat, 1);

2765:   PetscCall(PetscLogEventBegin(MAT_MultHermitianTranspose, mat, x, y, 0));
2766: #if defined(PETSC_USE_COMPLEX)
2767:   if (mat->ops->multhermitiantranspose || (mat->hermitian == PETSC_BOOL3_TRUE && mat->ops->mult)) {
2768:     PetscCall(VecLockReadPush(x));
2769:     if (mat->ops->multhermitiantranspose) PetscUseTypeMethod(mat, multhermitiantranspose, x, y);
2770:     else PetscUseTypeMethod(mat, mult, x, y);
2771:     PetscCall(VecLockReadPop(x));
2772:   } else {
2773:     Vec w;
2774:     PetscCall(VecDuplicate(x, &w));
2775:     PetscCall(VecCopy(x, w));
2776:     PetscCall(VecConjugate(w));
2777:     PetscCall(MatMultTranspose(mat, w, y));
2778:     PetscCall(VecDestroy(&w));
2779:     PetscCall(VecConjugate(y));
2780:   }
2781:   PetscCall(PetscObjectStateIncrease((PetscObject)y));
2782: #else
2783:   PetscCall(MatMultTranspose(mat, x, y));
2784: #endif
2785:   PetscCall(PetscLogEventEnd(MAT_MultHermitianTranspose, mat, x, y, 0));
2786:   PetscFunctionReturn(PETSC_SUCCESS);
2787: }

2789: /*@
2790:   MatMultAdd -  Computes $v3 = v2 + A * v1$.

2792:   Neighbor-wise Collective

2794:   Input Parameters:
2795: + mat - the matrix
2796: . v1  - the vector to be multiplied by `mat`
2797: - v2  - the vector to be added to the result

2799:   Output Parameter:
2800: . v3 - the result

2802:   Level: beginner

2804:   Note:
2805:   The vectors `v1` and `v3` cannot be the same.  I.e., one cannot
2806:   call `MatMultAdd`(A,v1,v2,v1).

2808: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMult()`, `MatMultTransposeAdd()`
2809: @*/
2810: PetscErrorCode MatMultAdd(Mat mat, Vec v1, Vec v2, Vec v3)
2811: {
2812:   PetscFunctionBegin;

2819:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2820:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2821:   PetscCheck(mat->cmap->N == v1->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v1: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v1->map->N);
2822:   /* PetscCheck(mat->rmap->N == v2->map->N,PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Mat mat,Vec v2: global dim %" PetscInt_FMT " %" PetscInt_FMT,mat->rmap->N,v2->map->N);
2823:      PetscCheck(mat->rmap->N == v3->map->N,PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Mat mat,Vec v3: global dim %" PetscInt_FMT " %" PetscInt_FMT,mat->rmap->N,v3->map->N); */
2824:   PetscCheck(mat->rmap->n == v3->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec v3: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, v3->map->n);
2825:   PetscCheck(mat->rmap->n == v2->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec v2: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, v2->map->n);
2826:   PetscCheck(v1 != v3, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "v1 and v3 must be different vectors");
2827:   MatCheckPreallocated(mat, 1);

2829:   PetscCall(PetscLogEventBegin(MAT_MultAdd, mat, v1, v2, v3));
2830:   PetscCall(VecLockReadPush(v1));
2831:   PetscUseTypeMethod(mat, multadd, v1, v2, v3);
2832:   PetscCall(VecLockReadPop(v1));
2833:   PetscCall(PetscLogEventEnd(MAT_MultAdd, mat, v1, v2, v3));
2834:   PetscCall(PetscObjectStateIncrease((PetscObject)v3));
2835:   PetscFunctionReturn(PETSC_SUCCESS);
2836: }

2838: /*@
2839:   MatMultTransposeAdd - Computes $v3 = v2 + A^T * v1$.

2841:   Neighbor-wise Collective

2843:   Input Parameters:
2844: + mat - the matrix
2845: . v1  - the vector to be multiplied by the transpose of the matrix
2846: - v2  - the vector to be added to the result

2848:   Output Parameter:
2849: . v3 - the result

2851:   Level: beginner

2853:   Note:
2854:   The vectors `v1` and `v3` cannot be the same.  I.e., one cannot
2855:   call `MatMultTransposeAdd`(A,v1,v2,v1).

2857: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMultAdd()`, `MatMult()`
2858: @*/
2859: PetscErrorCode MatMultTransposeAdd(Mat mat, Vec v1, Vec v2, Vec v3)
2860: {
2861:   PetscErrorCode (*op)(Mat, Vec, Vec, Vec) = (!mat->ops->multtransposeadd && mat->symmetric) ? mat->ops->multadd : mat->ops->multtransposeadd;

2863:   PetscFunctionBegin;

2870:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2871:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2872:   PetscCheck(mat->rmap->N == v1->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v1: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, v1->map->N);
2873:   PetscCheck(mat->cmap->N == v2->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v2: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v2->map->N);
2874:   PetscCheck(mat->cmap->N == v3->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v3: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v3->map->N);
2875:   PetscCheck(v1 != v3, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "v1 and v3 must be different vectors");
2876:   PetscCheck(op, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2877:   MatCheckPreallocated(mat, 1);

2879:   PetscCall(PetscLogEventBegin(MAT_MultTransposeAdd, mat, v1, v2, v3));
2880:   PetscCall(VecLockReadPush(v1));
2881:   PetscCall((*op)(mat, v1, v2, v3));
2882:   PetscCall(VecLockReadPop(v1));
2883:   PetscCall(PetscLogEventEnd(MAT_MultTransposeAdd, mat, v1, v2, v3));
2884:   PetscCall(PetscObjectStateIncrease((PetscObject)v3));
2885:   PetscFunctionReturn(PETSC_SUCCESS);
2886: }

2888: /*@
2889:   MatMultHermitianTransposeAdd - Computes $v3 = v2 + A^H * v1$.

2891:   Neighbor-wise Collective

2893:   Input Parameters:
2894: + mat - the matrix
2895: . v1  - the vector to be multiplied by the Hermitian transpose
2896: - v2  - the vector to be added to the result

2898:   Output Parameter:
2899: . v3 - the result

2901:   Level: beginner

2903:   Note:
2904:   The vectors `v1` and `v3` cannot be the same.  I.e., one cannot
2905:   call `MatMultHermitianTransposeAdd`(A,v1,v2,v1).

2907: .seealso: [](ch_matrices), `Mat`, `MatMultHermitianTranspose()`, `MatMultTranspose()`, `MatMultAdd()`, `MatMult()`
2908: @*/
2909: PetscErrorCode MatMultHermitianTransposeAdd(Mat mat, Vec v1, Vec v2, Vec v3)
2910: {
2911:   PetscFunctionBegin;

2918:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2919:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2920:   PetscCheck(v1 != v3, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "v1 and v3 must be different vectors");
2921:   PetscCheck(mat->rmap->N == v1->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v1: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, v1->map->N);
2922:   PetscCheck(mat->cmap->N == v2->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v2: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v2->map->N);
2923:   PetscCheck(mat->cmap->N == v3->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v3: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v3->map->N);
2924:   MatCheckPreallocated(mat, 1);

2926:   PetscCall(PetscLogEventBegin(MAT_MultHermitianTransposeAdd, mat, v1, v2, v3));
2927:   PetscCall(VecLockReadPush(v1));
2928:   if (mat->ops->multhermitiantransposeadd) PetscUseTypeMethod(mat, multhermitiantransposeadd, v1, v2, v3);
2929:   else {
2930:     Vec w, z;
2931:     PetscCall(VecDuplicate(v1, &w));
2932:     PetscCall(VecCopy(v1, w));
2933:     PetscCall(VecConjugate(w));
2934:     PetscCall(VecDuplicate(v3, &z));
2935:     PetscCall(MatMultTranspose(mat, w, z));
2936:     PetscCall(VecDestroy(&w));
2937:     PetscCall(VecConjugate(z));
2938:     if (v2 != v3) {
2939:       PetscCall(VecWAXPY(v3, 1.0, v2, z));
2940:     } else {
2941:       PetscCall(VecAXPY(v3, 1.0, z));
2942:     }
2943:     PetscCall(VecDestroy(&z));
2944:   }
2945:   PetscCall(VecLockReadPop(v1));
2946:   PetscCall(PetscLogEventEnd(MAT_MultHermitianTransposeAdd, mat, v1, v2, v3));
2947:   PetscCall(PetscObjectStateIncrease((PetscObject)v3));
2948:   PetscFunctionReturn(PETSC_SUCCESS);
2949: }

2951: /*@
2952:   MatGetFactorType - gets the type of factorization a matrix is

2954:   Not Collective

2956:   Input Parameter:
2957: . mat - the matrix

2959:   Output Parameter:
2960: . t - the type, one of `MAT_FACTOR_NONE`, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ILU`, `MAT_FACTOR_ICC,MAT_FACTOR_ILUDT`, `MAT_FACTOR_QR`

2962:   Level: intermediate

2964: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorType`, `MatGetFactor()`, `MatSetFactorType()`, `MAT_FACTOR_NONE`, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ILU`,
2965:           `MAT_FACTOR_ICC`,`MAT_FACTOR_ILUDT`, `MAT_FACTOR_QR`
2966: @*/
2967: PetscErrorCode MatGetFactorType(Mat mat, MatFactorType *t)
2968: {
2969:   PetscFunctionBegin;
2972:   PetscAssertPointer(t, 2);
2973:   *t = mat->factortype;
2974:   PetscFunctionReturn(PETSC_SUCCESS);
2975: }

2977: /*@
2978:   MatSetFactorType - sets the type of factorization a matrix is

2980:   Logically Collective

2982:   Input Parameters:
2983: + mat - the matrix
2984: - t   - the type, one of `MAT_FACTOR_NONE`, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ILU`, `MAT_FACTOR_ICC,MAT_FACTOR_ILUDT`, `MAT_FACTOR_QR`

2986:   Level: intermediate

2988: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorType`, `MatGetFactor()`, `MatGetFactorType()`, `MAT_FACTOR_NONE`, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ILU`,
2989:           `MAT_FACTOR_ICC`,`MAT_FACTOR_ILUDT`, `MAT_FACTOR_QR`
2990: @*/
2991: PetscErrorCode MatSetFactorType(Mat mat, MatFactorType t)
2992: {
2993:   PetscFunctionBegin;
2996:   mat->factortype = t;
2997:   PetscFunctionReturn(PETSC_SUCCESS);
2998: }

3000: /*@
3001:   MatGetInfo - Returns information about matrix storage (number of
3002:   nonzeros, memory, etc.).

3004:   Collective if `MAT_GLOBAL_MAX` or `MAT_GLOBAL_SUM` is used as the flag

3006:   Input Parameters:
3007: + mat  - the matrix
3008: - flag - flag indicating the type of parameters to be returned (`MAT_LOCAL` - local matrix, `MAT_GLOBAL_MAX` - maximum over all processors, `MAT_GLOBAL_SUM` - sum over all processors)

3010:   Output Parameter:
3011: . info - matrix information context

3013:   Options Database Key:
3014: . -mat_view ::ascii_info - print matrix info to `PETSC_STDOUT`

3016:   Level: intermediate

3018:   Notes:
3019:   The `MatInfo` context contains a variety of matrix data, including
3020:   number of nonzeros allocated and used, number of mallocs during
3021:   matrix assembly, etc.  Additional information for factored matrices
3022:   is provided (such as the fill ratio, number of mallocs during
3023:   factorization, etc.).

3025:   Example:
3026:   See the file ${PETSC_DIR}/include/petscmat.h for a complete list of
3027:   data within the `MatInfo` context.  For example,
3028: .vb
3029:       MatInfo info;
3030:       Mat     A;
3031:       double  mal, nz_a, nz_u;

3033:       MatGetInfo(A, MAT_LOCAL, &info);
3034:       mal  = info.mallocs;
3035:       nz_a = info.nz_allocated;
3036: .ve

3038:   Fortran Note:
3039:   Declare info as a `MatInfo` array of dimension `MAT_INFO_SIZE`, and then extract the parameters
3040:   of interest.  See the file ${PETSC_DIR}/include/petsc/finclude/petscmat.h
3041:   a complete list of parameter names.
3042: .vb
3043:       MatInfo info(MAT_INFO_SIZE)
3044:       double  precision mal, nz_a
3045:       Mat     A
3046:       integer ierr

3048:       call MatGetInfo(A, MAT_LOCAL, info, ierr)
3049:       mal = info(MAT_INFO_MALLOCS)
3050:       nz_a = info(MAT_INFO_NZ_ALLOCATED)
3051: .ve

3053: .seealso: [](ch_matrices), `Mat`, `MatInfo`, `MatStashGetInfo()`
3054: @*/
3055: PetscErrorCode MatGetInfo(Mat mat, MatInfoType flag, MatInfo *info)
3056: {
3057:   PetscFunctionBegin;
3060:   PetscAssertPointer(info, 3);
3061:   MatCheckPreallocated(mat, 1);
3062:   PetscUseTypeMethod(mat, getinfo, flag, info);
3063:   PetscFunctionReturn(PETSC_SUCCESS);
3064: }

3066: /*
3067:    This is used by external packages where it is not easy to get the info from the actual
3068:    matrix factorization.
3069: */
3070: PetscErrorCode MatGetInfo_External(Mat A, MatInfoType flag, MatInfo *info)
3071: {
3072:   PetscFunctionBegin;
3073:   PetscCall(PetscMemzero(info, sizeof(MatInfo)));
3074:   PetscFunctionReturn(PETSC_SUCCESS);
3075: }

3077: /*@
3078:   MatLUFactor - Performs in-place LU factorization of matrix.

3080:   Collective

3082:   Input Parameters:
3083: + mat  - the matrix
3084: . row  - row permutation
3085: . col  - column permutation
3086: - info - options for factorization, includes
3087: .vb
3088:           fill - expected fill as ratio of original fill.
3089:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3090:                    Run with the option -info to determine an optimal value to use
3091: .ve

3093:   Level: developer

3095:   Notes:
3096:   Most users should employ the `KSP` interface for linear solvers
3097:   instead of working directly with matrix algebra routines such as this.
3098:   See, e.g., `KSPCreate()`.

3100:   This changes the state of the matrix to a factored matrix; it cannot be used
3101:   for example with `MatSetValues()` unless one first calls `MatSetUnfactored()`.

3103:   This is really in-place only for dense matrices, the preferred approach is to use `MatGetFactor()`, `MatLUFactorSymbolic()`, and `MatLUFactorNumeric()`
3104:   when not using `KSP`.

3106:   Developer Note:
3107:   The Fortran interface is not autogenerated as the
3108:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

3110: .seealso: [](ch_matrices), [Matrix Factorization](sec_matfactor), `Mat`, `MatFactorType`, `MatLUFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`,
3111:           `MatGetOrdering()`, `MatSetUnfactored()`, `MatFactorInfo`, `MatGetFactor()`
3112: @*/
3113: PetscErrorCode MatLUFactor(Mat mat, IS row, IS col, const MatFactorInfo *info)
3114: {
3115:   MatFactorInfo tinfo;

3117:   PetscFunctionBegin;
3121:   if (info) PetscAssertPointer(info, 4);
3123:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3124:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3125:   MatCheckPreallocated(mat, 1);
3126:   if (!info) {
3127:     PetscCall(MatFactorInfoInitialize(&tinfo));
3128:     info = &tinfo;
3129:   }

3131:   PetscCall(PetscLogEventBegin(MAT_LUFactor, mat, row, col, 0));
3132:   PetscUseTypeMethod(mat, lufactor, row, col, info);
3133:   PetscCall(PetscLogEventEnd(MAT_LUFactor, mat, row, col, 0));
3134:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
3135:   PetscFunctionReturn(PETSC_SUCCESS);
3136: }

3138: /*@
3139:   MatILUFactor - Performs in-place ILU factorization of matrix.

3141:   Collective

3143:   Input Parameters:
3144: + mat  - the matrix
3145: . row  - row permutation
3146: . col  - column permutation
3147: - info - structure containing
3148: .vb
3149:       levels - number of levels of fill.
3150:       expected fill - as ratio of original fill.
3151:       1 or 0 - indicating force fill on diagonal (improves robustness for matrices
3152:                 missing diagonal entries)
3153: .ve

3155:   Level: developer

3157:   Notes:
3158:   Most users should employ the `KSP` interface for linear solvers
3159:   instead of working directly with matrix algebra routines such as this.
3160:   See, e.g., `KSPCreate()`.

3162:   Probably really in-place only when level of fill is zero, otherwise allocates
3163:   new space to store factored matrix and deletes previous memory. The preferred approach is to use `MatGetFactor()`, `MatILUFactorSymbolic()`, and `MatILUFactorNumeric()`
3164:   when not using `KSP`.

3166:   Developer Note:
3167:   The Fortran interface is not autogenerated as the
3168:   interface definition cannot be generated correctly [due to MatFactorInfo]

3170: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatILUFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`, `MatFactorInfo`
3171: @*/
3172: PetscErrorCode MatILUFactor(Mat mat, IS row, IS col, const MatFactorInfo *info)
3173: {
3174:   PetscFunctionBegin;
3178:   PetscAssertPointer(info, 4);
3180:   PetscCheck(mat->rmap->N == mat->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "matrix must be square");
3181:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3182:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3183:   MatCheckPreallocated(mat, 1);

3185:   PetscCall(PetscLogEventBegin(MAT_ILUFactor, mat, row, col, 0));
3186:   PetscUseTypeMethod(mat, ilufactor, row, col, info);
3187:   PetscCall(PetscLogEventEnd(MAT_ILUFactor, mat, row, col, 0));
3188:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
3189:   PetscFunctionReturn(PETSC_SUCCESS);
3190: }

3192: /*@
3193:   MatLUFactorSymbolic - Performs symbolic LU factorization of matrix.
3194:   Call this routine before calling `MatLUFactorNumeric()` and after `MatGetFactor()`.

3196:   Collective

3198:   Input Parameters:
3199: + fact - the factor matrix obtained with `MatGetFactor()`
3200: . mat  - the matrix
3201: . row  - the row permutation
3202: . col  - the column permutation
3203: - info - options for factorization, includes
3204: .vb
3205:           fill - expected fill as ratio of original fill. Run with the option -info to determine an optimal value to use
3206:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3207: .ve

3209:   Level: developer

3211:   Notes:
3212:   See [Matrix Factorization](sec_matfactor) for additional information about factorizations

3214:   Most users should employ the simplified `KSP` interface for linear solvers
3215:   instead of working directly with matrix algebra routines such as this.
3216:   See, e.g., `KSPCreate()`.

3218:   Developer Note:
3219:   The Fortran interface is not autogenerated as the
3220:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

3222: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatLUFactor()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`, `MatFactorInfo`, `MatFactorInfoInitialize()`
3223: @*/
3224: PetscErrorCode MatLUFactorSymbolic(Mat fact, Mat mat, IS row, IS col, const MatFactorInfo *info)
3225: {
3226:   MatFactorInfo tinfo;

3228:   PetscFunctionBegin;
3233:   if (info) PetscAssertPointer(info, 5);
3236:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3237:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3238:   MatCheckPreallocated(mat, 2);
3239:   if (!info) {
3240:     PetscCall(MatFactorInfoInitialize(&tinfo));
3241:     info = &tinfo;
3242:   }

3244:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_LUFactorSymbolic, mat, row, col, 0));
3245:   PetscUseTypeMethod(fact, lufactorsymbolic, mat, row, col, info);
3246:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_LUFactorSymbolic, mat, row, col, 0));
3247:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3248:   PetscFunctionReturn(PETSC_SUCCESS);
3249: }

3251: /*@
3252:   MatLUFactorNumeric - Performs numeric LU factorization of a matrix.
3253:   Call this routine after first calling `MatLUFactorSymbolic()` and `MatGetFactor()`.

3255:   Collective

3257:   Input Parameters:
3258: + fact - the factor matrix obtained with `MatGetFactor()`
3259: . mat  - the matrix
3260: - info - options for factorization

3262:   Level: developer

3264:   Notes:
3265:   See `MatLUFactor()` for in-place factorization.  See
3266:   `MatCholeskyFactorNumeric()` for the symmetric, positive definite case.

3268:   Most users should employ the `KSP` interface for linear solvers
3269:   instead of working directly with matrix algebra routines such as this.
3270:   See, e.g., `KSPCreate()`.

3272:   Developer Note:
3273:   The Fortran interface is not autogenerated as the
3274:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

3276: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatFactorInfo`, `MatLUFactorSymbolic()`, `MatLUFactor()`, `MatCholeskyFactor()`
3277: @*/
3278: PetscErrorCode MatLUFactorNumeric(Mat fact, Mat mat, const MatFactorInfo *info)
3279: {
3280:   MatFactorInfo tinfo;

3282:   PetscFunctionBegin;
3287:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3288:   PetscCheck(mat->rmap->N == (fact)->rmap->N && mat->cmap->N == (fact)->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Mat fact: global dimensions are different %" PetscInt_FMT " should = %" PetscInt_FMT " %" PetscInt_FMT " should = %" PetscInt_FMT,
3289:              mat->rmap->N, (fact)->rmap->N, mat->cmap->N, (fact)->cmap->N);

3291:   MatCheckPreallocated(mat, 2);
3292:   if (!info) {
3293:     PetscCall(MatFactorInfoInitialize(&tinfo));
3294:     info = &tinfo;
3295:   }

3297:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_LUFactorNumeric, mat, fact, 0, 0));
3298:   else PetscCall(PetscLogEventBegin(MAT_LUFactor, mat, fact, 0, 0));
3299:   PetscUseTypeMethod(fact, lufactornumeric, mat, info);
3300:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_LUFactorNumeric, mat, fact, 0, 0));
3301:   else PetscCall(PetscLogEventEnd(MAT_LUFactor, mat, fact, 0, 0));
3302:   PetscCall(MatViewFromOptions(fact, NULL, "-mat_factor_view"));
3303:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3304:   PetscFunctionReturn(PETSC_SUCCESS);
3305: }

3307: /*@
3308:   MatCholeskyFactor - Performs in-place Cholesky factorization of a
3309:   symmetric matrix.

3311:   Collective

3313:   Input Parameters:
3314: + mat  - the matrix
3315: . perm - row and column permutations
3316: - info - expected fill as ratio of original fill

3318:   Level: developer

3320:   Notes:
3321:   See `MatLUFactor()` for the nonsymmetric case.  See also `MatGetFactor()`,
3322:   `MatCholeskyFactorSymbolic()`, and `MatCholeskyFactorNumeric()`.

3324:   Most users should employ the `KSP` interface for linear solvers
3325:   instead of working directly with matrix algebra routines such as this.
3326:   See, e.g., `KSPCreate()`.

3328:   Developer Note:
3329:   The Fortran interface is not autogenerated as the
3330:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

3332: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatFactorInfo`, `MatLUFactor()`, `MatCholeskyFactorSymbolic()`, `MatCholeskyFactorNumeric()`
3333:           `MatGetOrdering()`
3334: @*/
3335: PetscErrorCode MatCholeskyFactor(Mat mat, IS perm, const MatFactorInfo *info)
3336: {
3337:   MatFactorInfo tinfo;

3339:   PetscFunctionBegin;
3342:   if (info) PetscAssertPointer(info, 3);
3344:   PetscCheck(mat->rmap->N == mat->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "Matrix must be square");
3345:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3346:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3347:   MatCheckPreallocated(mat, 1);
3348:   if (!info) {
3349:     PetscCall(MatFactorInfoInitialize(&tinfo));
3350:     info = &tinfo;
3351:   }

3353:   PetscCall(PetscLogEventBegin(MAT_CholeskyFactor, mat, perm, 0, 0));
3354:   PetscUseTypeMethod(mat, choleskyfactor, perm, info);
3355:   PetscCall(PetscLogEventEnd(MAT_CholeskyFactor, mat, perm, 0, 0));
3356:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
3357:   PetscFunctionReturn(PETSC_SUCCESS);
3358: }

3360: /*@
3361:   MatCholeskyFactorSymbolic - Performs symbolic Cholesky factorization
3362:   of a symmetric matrix.

3364:   Collective

3366:   Input Parameters:
3367: + fact - the factor matrix obtained with `MatGetFactor()`
3368: . mat  - the matrix
3369: . perm - row and column permutations
3370: - info - options for factorization, includes
3371: .vb
3372:           fill - expected fill as ratio of original fill.
3373:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3374:                    Run with the option -info to determine an optimal value to use
3375: .ve

3377:   Level: developer

3379:   Notes:
3380:   See `MatLUFactorSymbolic()` for the nonsymmetric case.  See also
3381:   `MatCholeskyFactor()` and `MatCholeskyFactorNumeric()`.

3383:   Most users should employ the `KSP` interface for linear solvers
3384:   instead of working directly with matrix algebra routines such as this.
3385:   See, e.g., `KSPCreate()`.

3387:   Developer Note:
3388:   The Fortran interface is not autogenerated as the
3389:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

3391: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorInfo`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactor()`, `MatCholeskyFactorNumeric()`
3392:           `MatGetOrdering()`
3393: @*/
3394: PetscErrorCode MatCholeskyFactorSymbolic(Mat fact, Mat mat, IS perm, const MatFactorInfo *info)
3395: {
3396:   MatFactorInfo tinfo;

3398:   PetscFunctionBegin;
3402:   if (info) PetscAssertPointer(info, 4);
3405:   PetscCheck(mat->rmap->N == mat->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "Matrix must be square");
3406:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3407:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3408:   MatCheckPreallocated(mat, 2);
3409:   if (!info) {
3410:     PetscCall(MatFactorInfoInitialize(&tinfo));
3411:     info = &tinfo;
3412:   }

3414:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_CholeskyFactorSymbolic, mat, perm, 0, 0));
3415:   PetscUseTypeMethod(fact, choleskyfactorsymbolic, mat, perm, info);
3416:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_CholeskyFactorSymbolic, mat, perm, 0, 0));
3417:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3418:   PetscFunctionReturn(PETSC_SUCCESS);
3419: }

3421: /*@
3422:   MatCholeskyFactorNumeric - Performs numeric Cholesky factorization
3423:   of a symmetric matrix. Call this routine after first calling `MatGetFactor()` and
3424:   `MatCholeskyFactorSymbolic()`.

3426:   Collective

3428:   Input Parameters:
3429: + fact - the factor matrix obtained with `MatGetFactor()`, where the factored values are stored
3430: . mat  - the initial matrix that is to be factored
3431: - info - options for factorization

3433:   Level: developer

3435:   Note:
3436:   Most users should employ the `KSP` interface for linear solvers
3437:   instead of working directly with matrix algebra routines such as this.
3438:   See, e.g., `KSPCreate()`.

3440:   Developer Note:
3441:   The Fortran interface is not autogenerated as the
3442:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

3444: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorInfo`, `MatGetFactor()`, `MatCholeskyFactorSymbolic()`, `MatCholeskyFactor()`, `MatLUFactorNumeric()`
3445: @*/
3446: PetscErrorCode MatCholeskyFactorNumeric(Mat fact, Mat mat, const MatFactorInfo *info)
3447: {
3448:   MatFactorInfo tinfo;

3450:   PetscFunctionBegin;
3455:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3456:   PetscCheck(mat->rmap->N == (fact)->rmap->N && mat->cmap->N == (fact)->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Mat fact: global dim %" PetscInt_FMT " should = %" PetscInt_FMT " %" PetscInt_FMT " should = %" PetscInt_FMT,
3457:              mat->rmap->N, (fact)->rmap->N, mat->cmap->N, (fact)->cmap->N);
3458:   MatCheckPreallocated(mat, 2);
3459:   if (!info) {
3460:     PetscCall(MatFactorInfoInitialize(&tinfo));
3461:     info = &tinfo;
3462:   }

3464:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_CholeskyFactorNumeric, mat, fact, 0, 0));
3465:   else PetscCall(PetscLogEventBegin(MAT_CholeskyFactor, mat, fact, 0, 0));
3466:   PetscUseTypeMethod(fact, choleskyfactornumeric, mat, info);
3467:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_CholeskyFactorNumeric, mat, fact, 0, 0));
3468:   else PetscCall(PetscLogEventEnd(MAT_CholeskyFactor, mat, fact, 0, 0));
3469:   PetscCall(MatViewFromOptions(fact, NULL, "-mat_factor_view"));
3470:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3471:   PetscFunctionReturn(PETSC_SUCCESS);
3472: }

3474: /*@
3475:   MatQRFactor - Performs in-place QR factorization of matrix.

3477:   Collective

3479:   Input Parameters:
3480: + mat  - the matrix
3481: . col  - column permutation
3482: - info - options for factorization, includes
3483: .vb
3484:           fill - expected fill as ratio of original fill.
3485:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3486:                    Run with the option -info to determine an optimal value to use
3487: .ve

3489:   Level: developer

3491:   Notes:
3492:   Most users should employ the `KSP` interface for linear solvers
3493:   instead of working directly with matrix algebra routines such as this.
3494:   See, e.g., `KSPCreate()`.

3496:   This changes the state of the matrix to a factored matrix; it cannot be used
3497:   for example with `MatSetValues()` unless one first calls `MatSetUnfactored()`.

3499:   Developer Note:
3500:   The Fortran interface is not autogenerated as the
3501:   interface definition cannot be generated correctly [due to MatFactorInfo]

3503: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorInfo`, `MatGetFactor()`, `MatQRFactorSymbolic()`, `MatQRFactorNumeric()`, `MatLUFactor()`,
3504:           `MatSetUnfactored()`
3505: @*/
3506: PetscErrorCode MatQRFactor(Mat mat, IS col, const MatFactorInfo *info)
3507: {
3508:   PetscFunctionBegin;
3511:   if (info) PetscAssertPointer(info, 3);
3513:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3514:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3515:   MatCheckPreallocated(mat, 1);
3516:   PetscCall(PetscLogEventBegin(MAT_QRFactor, mat, col, 0, 0));
3517:   PetscUseMethod(mat, "MatQRFactor_C", (Mat, IS, const MatFactorInfo *), (mat, col, info));
3518:   PetscCall(PetscLogEventEnd(MAT_QRFactor, mat, col, 0, 0));
3519:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
3520:   PetscFunctionReturn(PETSC_SUCCESS);
3521: }

3523: /*@
3524:   MatQRFactorSymbolic - Performs symbolic QR factorization of matrix.
3525:   Call this routine after `MatGetFactor()` but before calling `MatQRFactorNumeric()`.

3527:   Collective

3529:   Input Parameters:
3530: + fact - the factor matrix obtained with `MatGetFactor()`
3531: . mat  - the matrix
3532: . col  - column permutation
3533: - info - options for factorization, includes
3534: .vb
3535:           fill - expected fill as ratio of original fill.
3536:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3537:                    Run with the option -info to determine an optimal value to use
3538: .ve

3540:   Level: developer

3542:   Note:
3543:   Most users should employ the `KSP` interface for linear solvers
3544:   instead of working directly with matrix algebra routines such as this.
3545:   See, e.g., `KSPCreate()`.

3547:   Developer Note:
3548:   The Fortran interface is not autogenerated as the
3549:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

3551: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatFactorInfo`, `MatQRFactor()`, `MatQRFactorNumeric()`, `MatLUFactor()`, `MatFactorInfoInitialize()`
3552: @*/
3553: PetscErrorCode MatQRFactorSymbolic(Mat fact, Mat mat, IS col, const MatFactorInfo *info)
3554: {
3555:   MatFactorInfo tinfo;

3557:   PetscFunctionBegin;
3561:   if (info) PetscAssertPointer(info, 4);
3564:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3565:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3566:   MatCheckPreallocated(mat, 2);
3567:   if (!info) {
3568:     PetscCall(MatFactorInfoInitialize(&tinfo));
3569:     info = &tinfo;
3570:   }

3572:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_QRFactorSymbolic, fact, mat, col, 0));
3573:   PetscUseMethod(fact, "MatQRFactorSymbolic_C", (Mat, Mat, IS, const MatFactorInfo *), (fact, mat, col, info));
3574:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_QRFactorSymbolic, fact, mat, col, 0));
3575:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3576:   PetscFunctionReturn(PETSC_SUCCESS);
3577: }

3579: /*@
3580:   MatQRFactorNumeric - Performs numeric QR factorization of a matrix.
3581:   Call this routine after first calling `MatGetFactor()`, and `MatQRFactorSymbolic()`.

3583:   Collective

3585:   Input Parameters:
3586: + fact - the factor matrix obtained with `MatGetFactor()`
3587: . mat  - the matrix
3588: - info - options for factorization

3590:   Level: developer

3592:   Notes:
3593:   See `MatQRFactor()` for in-place factorization.

3595:   Most users should employ the `KSP` interface for linear solvers
3596:   instead of working directly with matrix algebra routines such as this.
3597:   See, e.g., `KSPCreate()`.

3599:   Developer Note:
3600:   The Fortran interface is not autogenerated as the
3601:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

3603: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorInfo`, `MatGetFactor()`, `MatQRFactor()`, `MatQRFactorSymbolic()`, `MatLUFactor()`
3604: @*/
3605: PetscErrorCode MatQRFactorNumeric(Mat fact, Mat mat, const MatFactorInfo *info)
3606: {
3607:   MatFactorInfo tinfo;

3609:   PetscFunctionBegin;
3614:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3615:   PetscCheck(mat->rmap->N == fact->rmap->N && mat->cmap->N == fact->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Mat fact: global dimensions are different %" PetscInt_FMT " should = %" PetscInt_FMT " %" PetscInt_FMT " should = %" PetscInt_FMT,
3616:              mat->rmap->N, (fact)->rmap->N, mat->cmap->N, (fact)->cmap->N);

3618:   MatCheckPreallocated(mat, 2);
3619:   if (!info) {
3620:     PetscCall(MatFactorInfoInitialize(&tinfo));
3621:     info = &tinfo;
3622:   }

3624:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_QRFactorNumeric, mat, fact, 0, 0));
3625:   else PetscCall(PetscLogEventBegin(MAT_QRFactor, mat, fact, 0, 0));
3626:   PetscUseMethod(fact, "MatQRFactorNumeric_C", (Mat, Mat, const MatFactorInfo *), (fact, mat, info));
3627:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_QRFactorNumeric, mat, fact, 0, 0));
3628:   else PetscCall(PetscLogEventEnd(MAT_QRFactor, mat, fact, 0, 0));
3629:   PetscCall(MatViewFromOptions(fact, NULL, "-mat_factor_view"));
3630:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3631:   PetscFunctionReturn(PETSC_SUCCESS);
3632: }

3634: /*@
3635:   MatSolve - Solves $A x = b$, given a factored matrix.

3637:   Neighbor-wise Collective

3639:   Input Parameters:
3640: + mat - the factored matrix
3641: - b   - the right-hand-side vector

3643:   Output Parameter:
3644: . x - the result vector

3646:   Level: developer

3648:   Notes:
3649:   The vectors `b` and `x` cannot be the same.  I.e., one cannot
3650:   call `MatSolve`(A,x,x).

3652:   Most users should employ the `KSP` interface for linear solvers
3653:   instead of working directly with matrix algebra routines such as this.
3654:   See, e.g., `KSPCreate()`.

3656: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatLUFactor()`, `MatSolveAdd()`, `MatSolveTranspose()`, `MatSolveTransposeAdd()`
3657: @*/
3658: PetscErrorCode MatSolve(Mat mat, Vec b, Vec x)
3659: {
3660:   PetscFunctionBegin;
3665:   PetscCheckSameComm(mat, 1, b, 2);
3666:   PetscCheckSameComm(mat, 1, x, 3);
3667:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
3668:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
3669:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
3670:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
3671:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
3672:   MatCheckPreallocated(mat, 1);

3674:   PetscCall(PetscLogEventBegin(MAT_Solve, mat, b, x, 0));
3675:   PetscCall(VecFlag(x, mat->factorerrortype));
3676:   if (mat->factorerrortype) {
3677:     PetscCall(PetscInfo(mat, "MatFactorError %d\n", mat->factorerrortype));
3678:   } else PetscUseTypeMethod(mat, solve, b, x);
3679:   PetscCall(PetscLogEventEnd(MAT_Solve, mat, b, x, 0));
3680:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
3681:   PetscFunctionReturn(PETSC_SUCCESS);
3682: }

3684: static PetscErrorCode MatMatSolve_Basic(Mat A, Mat B, Mat X, PetscBool trans)
3685: {
3686:   Vec      b, x;
3687:   PetscInt N, i;
3688:   PetscErrorCode (*f)(Mat, Vec, Vec);
3689:   PetscBool Abound, Bneedconv = PETSC_FALSE, Xneedconv = PETSC_FALSE;

3691:   PetscFunctionBegin;
3692:   if (A->factorerrortype) {
3693:     PetscCall(PetscInfo(A, "MatFactorError %d\n", A->factorerrortype));
3694:     PetscCall(MatSetInf(X));
3695:     PetscFunctionReturn(PETSC_SUCCESS);
3696:   }
3697:   f = (!trans || (!A->ops->solvetranspose && A->symmetric)) ? A->ops->solve : A->ops->solvetranspose;
3698:   PetscCheck(f, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Mat type %s", ((PetscObject)A)->type_name);
3699:   PetscCall(MatBoundToCPU(A, &Abound));
3700:   if (!Abound) {
3701:     PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &Bneedconv, MATSEQDENSE, MATMPIDENSE, ""));
3702:     PetscCall(PetscObjectTypeCompareAny((PetscObject)X, &Xneedconv, MATSEQDENSE, MATMPIDENSE, ""));
3703:   }
3704: #if PetscDefined(HAVE_CUDA)
3705:   if (Bneedconv) PetscCall(MatConvert(B, MATDENSECUDA, MAT_INPLACE_MATRIX, &B));
3706:   if (Xneedconv) PetscCall(MatConvert(X, MATDENSECUDA, MAT_INPLACE_MATRIX, &X));
3707: #elif PetscDefined(HAVE_HIP)
3708:   if (Bneedconv) PetscCall(MatConvert(B, MATDENSEHIP, MAT_INPLACE_MATRIX, &B));
3709:   if (Xneedconv) PetscCall(MatConvert(X, MATDENSEHIP, MAT_INPLACE_MATRIX, &X));
3710: #endif
3711:   PetscCall(MatGetSize(B, NULL, &N));
3712:   for (i = 0; i < N; i++) {
3713:     PetscCall(MatDenseGetColumnVecRead(B, i, &b));
3714:     PetscCall(MatDenseGetColumnVecWrite(X, i, &x));
3715:     PetscCall((*f)(A, b, x));
3716:     PetscCall(MatDenseRestoreColumnVecWrite(X, i, &x));
3717:     PetscCall(MatDenseRestoreColumnVecRead(B, i, &b));
3718:   }
3719:   if (Bneedconv) PetscCall(MatConvert(B, MATDENSE, MAT_INPLACE_MATRIX, &B));
3720:   if (Xneedconv) PetscCall(MatConvert(X, MATDENSE, MAT_INPLACE_MATRIX, &X));
3721:   PetscFunctionReturn(PETSC_SUCCESS);
3722: }

3724: /*@
3725:   MatMatSolve - Solves $A X = B$, given a factored matrix.

3727:   Neighbor-wise Collective

3729:   Input Parameters:
3730: + A - the factored matrix
3731: - B - the right-hand-side matrix `MATDENSE` (or sparse `MATAIJ`-- when using MUMPS)

3733:   Output Parameter:
3734: . X - the result matrix (dense matrix)

3736:   Level: developer

3738:   Note:
3739:   If `B` is a `MATDENSE` matrix then one can call `MatMatSolve`(A,B,B) except with `MATSOLVERMKL_CPARDISO`;
3740:   otherwise, `B` and `X` cannot be the same.

3742: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatSolve()`, `MatMatSolveTranspose()`, `MatLUFactor()`, `MatCholeskyFactor()`
3743: @*/
3744: PetscErrorCode MatMatSolve(Mat A, Mat B, Mat X)
3745: {
3746:   PetscFunctionBegin;
3751:   PetscCheckSameComm(A, 1, B, 2);
3752:   PetscCheckSameComm(A, 1, X, 3);
3753:   PetscCheck(A->cmap->N == X->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat X: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->cmap->N, X->rmap->N);
3754:   PetscCheck(A->rmap->N == B->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat B: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->N, B->rmap->N);
3755:   PetscCheck(X->cmap->N == B->cmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Solution matrix must have same number of columns as rhs matrix");
3756:   if (!A->rmap->N && !A->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
3757:   MatCheckPreallocated(A, 1);

3759:   PetscCall(PetscLogEventBegin(MAT_MatSolve, A, B, X, 0));
3760:   if (!A->ops->matsolve) {
3761:     PetscCall(PetscInfo(A, "Mat type %s using basic MatMatSolve\n", ((PetscObject)A)->type_name));
3762:     PetscCall(MatMatSolve_Basic(A, B, X, PETSC_FALSE));
3763:   } else PetscUseTypeMethod(A, matsolve, B, X);
3764:   PetscCall(PetscLogEventEnd(MAT_MatSolve, A, B, X, 0));
3765:   PetscCall(PetscObjectStateIncrease((PetscObject)X));
3766:   PetscFunctionReturn(PETSC_SUCCESS);
3767: }

3769: /*@
3770:   MatMatSolveTranspose - Solves $A^T X = B $, given a factored matrix.

3772:   Neighbor-wise Collective

3774:   Input Parameters:
3775: + A - the factored matrix
3776: - B - the right-hand-side matrix  (`MATDENSE` matrix)

3778:   Output Parameter:
3779: . X - the result matrix (dense matrix)

3781:   Level: developer

3783:   Note:
3784:   The matrices `B` and `X` cannot be the same.  I.e., one cannot
3785:   call `MatMatSolveTranspose`(A,X,X).

3787: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatSolveTranspose()`, `MatMatSolve()`, `MatLUFactor()`, `MatCholeskyFactor()`
3788: @*/
3789: PetscErrorCode MatMatSolveTranspose(Mat A, Mat B, Mat X)
3790: {
3791:   PetscFunctionBegin;
3796:   PetscCheckSameComm(A, 1, B, 2);
3797:   PetscCheckSameComm(A, 1, X, 3);
3798:   PetscCheck(X != B, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_IDN, "X and B must be different matrices");
3799:   PetscCheck(A->cmap->N == X->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat X: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->cmap->N, X->rmap->N);
3800:   PetscCheck(A->rmap->N == B->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat B: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->N, B->rmap->N);
3801:   PetscCheck(A->rmap->n == B->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat A,Mat B: local dim %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->n, B->rmap->n);
3802:   PetscCheck(X->cmap->N >= B->cmap->N, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Solution matrix must have same number of columns as rhs matrix");
3803:   if (!A->rmap->N && !A->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
3804:   MatCheckPreallocated(A, 1);

3806:   PetscCall(PetscLogEventBegin(MAT_MatSolve, A, B, X, 0));
3807:   if (!A->ops->matsolvetranspose) {
3808:     PetscCall(PetscInfo(A, "Mat type %s using basic MatMatSolveTranspose\n", ((PetscObject)A)->type_name));
3809:     PetscCall(MatMatSolve_Basic(A, B, X, PETSC_TRUE));
3810:   } else PetscUseTypeMethod(A, matsolvetranspose, B, X);
3811:   PetscCall(PetscLogEventEnd(MAT_MatSolve, A, B, X, 0));
3812:   PetscCall(PetscObjectStateIncrease((PetscObject)X));
3813:   PetscFunctionReturn(PETSC_SUCCESS);
3814: }

3816: /*@
3817:   MatMatTransposeSolve - Solves $A X = B^T$, given a factored matrix.

3819:   Neighbor-wise Collective

3821:   Input Parameters:
3822: + A  - the factored matrix
3823: - Bt - the transpose of right-hand-side matrix as a `MATDENSE`

3825:   Output Parameter:
3826: . X - the result matrix (dense matrix)

3828:   Level: developer

3830:   Note:
3831:   For MUMPS, it only supports centralized sparse compressed column format on the host processor for right-hand side matrix. User must create `Bt` in sparse compressed row
3832:   format on the host processor and call `MatMatTransposeSolve()` to implement MUMPS' `MatMatSolve()`.

3834: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatMatSolve()`, `MatMatSolveTranspose()`, `MatLUFactor()`, `MatCholeskyFactor()`
3835: @*/
3836: PetscErrorCode MatMatTransposeSolve(Mat A, Mat Bt, Mat X)
3837: {
3838:   PetscFunctionBegin;
3843:   PetscCheckSameComm(A, 1, Bt, 2);
3844:   PetscCheckSameComm(A, 1, X, 3);

3846:   PetscCheck(X != Bt, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_IDN, "X and B must be different matrices");
3847:   PetscCheck(A->cmap->N == X->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat X: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->cmap->N, X->rmap->N);
3848:   PetscCheck(A->rmap->N == Bt->cmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat Bt: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->N, Bt->cmap->N);
3849:   PetscCheck(X->cmap->N >= Bt->rmap->N, PetscObjectComm((PetscObject)X), PETSC_ERR_ARG_SIZ, "Solution matrix must have same number of columns as row number of the rhs matrix");
3850:   if (!A->rmap->N && !A->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
3851:   PetscCheck(A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Unfactored matrix");
3852:   MatCheckPreallocated(A, 1);

3854:   PetscCall(PetscLogEventBegin(MAT_MatTrSolve, A, Bt, X, 0));
3855:   PetscUseTypeMethod(A, mattransposesolve, Bt, X);
3856:   PetscCall(PetscLogEventEnd(MAT_MatTrSolve, A, Bt, X, 0));
3857:   PetscCall(PetscObjectStateIncrease((PetscObject)X));
3858:   PetscFunctionReturn(PETSC_SUCCESS);
3859: }

3861: /*@
3862:   MatForwardSolve - Solves $ L x = b $, given a factored matrix, $A = LU $, or
3863:   $U^T*D^(1/2) x = b$, given a factored symmetric matrix, $A = U^T*D*U$,

3865:   Neighbor-wise Collective

3867:   Input Parameters:
3868: + mat - the factored matrix
3869: - b   - the right-hand-side vector

3871:   Output Parameter:
3872: . x - the result vector

3874:   Level: developer

3876:   Notes:
3877:   `MatSolve()` should be used for most applications, as it performs
3878:   a forward solve followed by a backward solve.

3880:   The vectors `b` and `x` cannot be the same,  i.e., one cannot
3881:   call `MatForwardSolve`(A,x,x).

3883:   For matrix in `MATSEQBAIJ` format with block size larger than 1,
3884:   the diagonal blocks are not implemented as $D = D^(1/2) * D^(1/2)$ yet.
3885:   `MatForwardSolve()` solves $U^T*D y = b$, and
3886:   `MatBackwardSolve()` solves $U x = y$.
3887:   Thus they do not provide a symmetric preconditioner.

3889: .seealso: [](ch_matrices), `Mat`, `MatBackwardSolve()`, `MatGetFactor()`, `MatSolve()`
3890: @*/
3891: PetscErrorCode MatForwardSolve(Mat mat, Vec b, Vec x)
3892: {
3893:   PetscFunctionBegin;
3898:   PetscCheckSameComm(mat, 1, b, 2);
3899:   PetscCheckSameComm(mat, 1, x, 3);
3900:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
3901:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
3902:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
3903:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
3904:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
3905:   MatCheckPreallocated(mat, 1);

3907:   PetscCall(PetscLogEventBegin(MAT_ForwardSolve, mat, b, x, 0));
3908:   PetscUseTypeMethod(mat, forwardsolve, b, x);
3909:   PetscCall(PetscLogEventEnd(MAT_ForwardSolve, mat, b, x, 0));
3910:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
3911:   PetscFunctionReturn(PETSC_SUCCESS);
3912: }

3914: /*@
3915:   MatBackwardSolve - Solves $U x = b$, given a factored matrix, $A = LU$.
3916:   $D^(1/2) U x = b$, given a factored symmetric matrix, $A = U^T*D*U$,

3918:   Neighbor-wise Collective

3920:   Input Parameters:
3921: + mat - the factored matrix
3922: - b   - the right-hand-side vector

3924:   Output Parameter:
3925: . x - the result vector

3927:   Level: developer

3929:   Notes:
3930:   `MatSolve()` should be used for most applications, as it performs
3931:   a forward solve followed by a backward solve.

3933:   The vectors `b` and `x` cannot be the same.  I.e., one cannot
3934:   call `MatBackwardSolve`(A,x,x).

3936:   For matrix in `MATSEQBAIJ` format with block size larger than 1,
3937:   the diagonal blocks are not implemented as $D = D^(1/2) * D^(1/2)$ yet.
3938:   `MatForwardSolve()` solves $U^T*D y = b$, and
3939:   `MatBackwardSolve()` solves $U x = y$.
3940:   Thus they do not provide a symmetric preconditioner.

3942: .seealso: [](ch_matrices), `Mat`, `MatForwardSolve()`, `MatGetFactor()`, `MatSolve()`
3943: @*/
3944: PetscErrorCode MatBackwardSolve(Mat mat, Vec b, Vec x)
3945: {
3946:   PetscFunctionBegin;
3951:   PetscCheckSameComm(mat, 1, b, 2);
3952:   PetscCheckSameComm(mat, 1, x, 3);
3953:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
3954:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
3955:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
3956:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
3957:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
3958:   MatCheckPreallocated(mat, 1);

3960:   PetscCall(PetscLogEventBegin(MAT_BackwardSolve, mat, b, x, 0));
3961:   PetscUseTypeMethod(mat, backwardsolve, b, x);
3962:   PetscCall(PetscLogEventEnd(MAT_BackwardSolve, mat, b, x, 0));
3963:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
3964:   PetscFunctionReturn(PETSC_SUCCESS);
3965: }

3967: /*@
3968:   MatSolveAdd - Computes $x = y + A^{-1}*b$, given a factored matrix.

3970:   Neighbor-wise Collective

3972:   Input Parameters:
3973: + mat - the factored matrix
3974: . b   - the right-hand-side vector
3975: - y   - the vector to be added to

3977:   Output Parameter:
3978: . x - the result vector

3980:   Level: developer

3982:   Note:
3983:   The vectors `b` and `x` cannot be the same.  I.e., one cannot
3984:   call `MatSolveAdd`(A,x,y,x).

3986: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatSolve()`, `MatGetFactor()`, `MatSolveTranspose()`, `MatSolveTransposeAdd()`
3987: @*/
3988: PetscErrorCode MatSolveAdd(Mat mat, Vec b, Vec y, Vec x)
3989: {
3990:   PetscScalar one = 1.0;
3991:   Vec         tmp;

3993:   PetscFunctionBegin;
3999:   PetscCheckSameComm(mat, 1, b, 2);
4000:   PetscCheckSameComm(mat, 1, y, 3);
4001:   PetscCheckSameComm(mat, 1, x, 4);
4002:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
4003:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
4004:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
4005:   PetscCheck(mat->rmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, y->map->N);
4006:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
4007:   PetscCheck(x->map->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Vec x,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, x->map->n, y->map->n);
4008:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4009:   MatCheckPreallocated(mat, 1);

4011:   PetscCall(PetscLogEventBegin(MAT_SolveAdd, mat, b, x, y));
4012:   PetscCall(VecFlag(x, mat->factorerrortype));
4013:   if (mat->factorerrortype) {
4014:     PetscCall(PetscInfo(mat, "MatFactorError %d\n", mat->factorerrortype));
4015:   } else if (mat->ops->solveadd) {
4016:     PetscUseTypeMethod(mat, solveadd, b, y, x);
4017:   } else {
4018:     /* do the solve then the add manually */
4019:     if (x != y) {
4020:       PetscCall(MatSolve(mat, b, x));
4021:       PetscCall(VecAXPY(x, one, y));
4022:     } else {
4023:       PetscCall(VecDuplicate(x, &tmp));
4024:       PetscCall(VecCopy(x, tmp));
4025:       PetscCall(MatSolve(mat, b, x));
4026:       PetscCall(VecAXPY(x, one, tmp));
4027:       PetscCall(VecDestroy(&tmp));
4028:     }
4029:   }
4030:   PetscCall(PetscLogEventEnd(MAT_SolveAdd, mat, b, x, y));
4031:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4032:   PetscFunctionReturn(PETSC_SUCCESS);
4033: }

4035: /*@
4036:   MatSolveTranspose - Solves $A^T x = b$, given a factored matrix.

4038:   Neighbor-wise Collective

4040:   Input Parameters:
4041: + mat - the factored matrix
4042: - b   - the right-hand-side vector

4044:   Output Parameter:
4045: . x - the result vector

4047:   Level: developer

4049:   Notes:
4050:   The vectors `b` and `x` cannot be the same.  I.e., one cannot
4051:   call `MatSolveTranspose`(A,x,x).

4053:   Most users should employ the `KSP` interface for linear solvers
4054:   instead of working directly with matrix algebra routines such as this.
4055:   See, e.g., `KSPCreate()`.

4057: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `KSP`, `MatSolve()`, `MatSolveAdd()`, `MatSolveTransposeAdd()`
4058: @*/
4059: PetscErrorCode MatSolveTranspose(Mat mat, Vec b, Vec x)
4060: {
4061:   PetscErrorCode (*f)(Mat, Vec, Vec) = (!mat->ops->solvetranspose && mat->symmetric) ? mat->ops->solve : mat->ops->solvetranspose;

4063:   PetscFunctionBegin;
4068:   PetscCheckSameComm(mat, 1, b, 2);
4069:   PetscCheckSameComm(mat, 1, x, 3);
4070:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
4071:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
4072:   PetscCheck(mat->cmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, b->map->N);
4073:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4074:   MatCheckPreallocated(mat, 1);
4075:   PetscCall(PetscLogEventBegin(MAT_SolveTranspose, mat, b, x, 0));
4076:   PetscCall(VecFlag(x, mat->factorerrortype));
4077:   if (mat->factorerrortype) {
4078:     PetscCall(PetscInfo(mat, "MatFactorError %d\n", mat->factorerrortype));
4079:   } else {
4080:     PetscCheck(f, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Matrix type %s", ((PetscObject)mat)->type_name);
4081:     PetscCall((*f)(mat, b, x));
4082:   }
4083:   PetscCall(PetscLogEventEnd(MAT_SolveTranspose, mat, b, x, 0));
4084:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4085:   PetscFunctionReturn(PETSC_SUCCESS);
4086: }

4088: /*@
4089:   MatSolveTransposeAdd - Computes $x = y + A^{-T} b$
4090:   factored matrix.

4092:   Neighbor-wise Collective

4094:   Input Parameters:
4095: + mat - the factored matrix
4096: . b   - the right-hand-side vector
4097: - y   - the vector to be added to

4099:   Output Parameter:
4100: . x - the result vector

4102:   Level: developer

4104:   Note:
4105:   The vectors `b` and `x` cannot be the same.  I.e., one cannot
4106:   call `MatSolveTransposeAdd`(A,x,y,x).

4108: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatSolve()`, `MatSolveAdd()`, `MatSolveTranspose()`
4109: @*/
4110: PetscErrorCode MatSolveTransposeAdd(Mat mat, Vec b, Vec y, Vec x)
4111: {
4112:   PetscScalar one = 1.0;
4113:   Vec         tmp;
4114:   PetscErrorCode (*f)(Mat, Vec, Vec, Vec) = (!mat->ops->solvetransposeadd && mat->symmetric) ? mat->ops->solveadd : mat->ops->solvetransposeadd;

4116:   PetscFunctionBegin;
4122:   PetscCheckSameComm(mat, 1, b, 2);
4123:   PetscCheckSameComm(mat, 1, y, 3);
4124:   PetscCheckSameComm(mat, 1, x, 4);
4125:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
4126:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
4127:   PetscCheck(mat->cmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, b->map->N);
4128:   PetscCheck(mat->cmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, y->map->N);
4129:   PetscCheck(x->map->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Vec x,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, x->map->n, y->map->n);
4130:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4131:   MatCheckPreallocated(mat, 1);

4133:   PetscCall(PetscLogEventBegin(MAT_SolveTransposeAdd, mat, b, x, y));
4134:   PetscCall(VecFlag(x, mat->factorerrortype));
4135:   if (mat->factorerrortype) {
4136:     PetscCall(PetscInfo(mat, "MatFactorError %d\n", mat->factorerrortype));
4137:   } else if (f) {
4138:     PetscCall((*f)(mat, b, y, x));
4139:   } else {
4140:     /* do the solve then the add manually */
4141:     if (x != y) {
4142:       PetscCall(MatSolveTranspose(mat, b, x));
4143:       PetscCall(VecAXPY(x, one, y));
4144:     } else {
4145:       PetscCall(VecDuplicate(x, &tmp));
4146:       PetscCall(VecCopy(x, tmp));
4147:       PetscCall(MatSolveTranspose(mat, b, x));
4148:       PetscCall(VecAXPY(x, one, tmp));
4149:       PetscCall(VecDestroy(&tmp));
4150:     }
4151:   }
4152:   PetscCall(PetscLogEventEnd(MAT_SolveTransposeAdd, mat, b, x, y));
4153:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4154:   PetscFunctionReturn(PETSC_SUCCESS);
4155: }

4157: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
4158: /*@
4159:   MatSOR - Computes relaxation (SOR, Gauss-Seidel) sweeps.

4161:   Neighbor-wise Collective

4163:   Input Parameters:
4164: + mat   - the matrix
4165: . b     - the right-hand side
4166: . omega - the relaxation factor
4167: . flag  - flag indicating the type of SOR (see below)
4168: . shift - diagonal shift
4169: . its   - the number of iterations
4170: - lits  - the number of local iterations

4172:   Output Parameter:
4173: . x - the solution (can contain an initial guess, use option `SOR_ZERO_INITIAL_GUESS` to indicate no guess)

4175:   SOR Flags:
4176: +     `SOR_FORWARD_SWEEP` - forward SOR
4177: .     `SOR_BACKWARD_SWEEP` - backward SOR
4178: .     `SOR_SYMMETRIC_SWEEP` - SSOR (symmetric SOR)
4179: .     `SOR_LOCAL_FORWARD_SWEEP` - local forward SOR
4180: .     `SOR_LOCAL_BACKWARD_SWEEP` - local forward SOR
4181: .     `SOR_LOCAL_SYMMETRIC_SWEEP` - local SSOR
4182: .     `SOR_EISENSTAT` - SOR with Eisenstat trick
4183: .     `SOR_APPLY_UPPER`, `SOR_APPLY_LOWER` - applies
4184:   upper/lower triangular part of matrix to
4185:   vector (with omega)
4186: -     `SOR_ZERO_INITIAL_GUESS` - zero initial guess

4188:   Level: developer

4190:   Notes:
4191:   `SOR_LOCAL_FORWARD_SWEEP`, `SOR_LOCAL_BACKWARD_SWEEP`, and
4192:   `SOR_LOCAL_SYMMETRIC_SWEEP` perform separate independent smoothings
4193:   on each processor.

4195:   Application programmers will not generally use `MatSOR()` directly,
4196:   but instead will employ the `KSP`/`PC` interface.

4198:   For `MATBAIJ`, `MATSBAIJ`, and `MATAIJ` matrices with Inodes this does a block SOR smoothing, otherwise it does a pointwise smoothing

4200:   Most users should employ the `KSP` interface for linear solvers
4201:   instead of working directly with matrix algebra routines such as this.
4202:   See, e.g., `KSPCreate()`.

4204:   Vectors `x` and `b` CANNOT be the same

4206:   The flags are implemented as bitwise inclusive or operations.
4207:   For example, use (`SOR_ZERO_INITIAL_GUESS` | `SOR_SYMMETRIC_SWEEP`)
4208:   to specify a zero initial guess for SSOR.

4210:   Developer Note:
4211:   We should add block SOR support for `MATAIJ` matrices with block size set to great than one and no inodes

4213: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `KSP`, `PC`, `MatGetFactor()`
4214: @*/
4215: PetscErrorCode MatSOR(Mat mat, Vec b, PetscReal omega, MatSORType flag, PetscReal shift, PetscInt its, PetscInt lits, Vec x)
4216: {
4217:   PetscFunctionBegin;
4222:   PetscCheckSameComm(mat, 1, b, 2);
4223:   PetscCheckSameComm(mat, 1, x, 8);
4224:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
4225:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4226:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
4227:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
4228:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
4229:   PetscCheck(its > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Relaxation requires global its %" PetscInt_FMT " positive", its);
4230:   PetscCheck(lits > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Relaxation requires local its %" PetscInt_FMT " positive", lits);
4231:   PetscCheck(b != x, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "b and x vector cannot be the same");

4233:   MatCheckPreallocated(mat, 1);
4234:   PetscCall(PetscLogEventBegin(MAT_SOR, mat, b, x, 0));
4235:   PetscUseTypeMethod(mat, sor, b, omega, flag, shift, its, lits, x);
4236:   PetscCall(PetscLogEventEnd(MAT_SOR, mat, b, x, 0));
4237:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4238:   PetscFunctionReturn(PETSC_SUCCESS);
4239: }

4241: /*
4242:       Default matrix copy routine.
4243: */
4244: PetscErrorCode MatCopy_Basic(Mat A, Mat B, MatStructure str)
4245: {
4246:   PetscInt           i, rstart = 0, rend = 0, nz;
4247:   const PetscInt    *cwork;
4248:   const PetscScalar *vwork;

4250:   PetscFunctionBegin;
4251:   if (B->assembled) PetscCall(MatZeroEntries(B));
4252:   if (str == SAME_NONZERO_PATTERN) {
4253:     PetscCall(MatGetOwnershipRange(A, &rstart, &rend));
4254:     for (i = rstart; i < rend; i++) {
4255:       PetscCall(MatGetRow(A, i, &nz, &cwork, &vwork));
4256:       PetscCall(MatSetValues(B, 1, &i, nz, cwork, vwork, INSERT_VALUES));
4257:       PetscCall(MatRestoreRow(A, i, &nz, &cwork, &vwork));
4258:     }
4259:   } else {
4260:     PetscCall(MatAYPX(B, 0.0, A, str));
4261:   }
4262:   PetscCall(MatAssemblyBegin(B, MAT_FINAL_ASSEMBLY));
4263:   PetscCall(MatAssemblyEnd(B, MAT_FINAL_ASSEMBLY));
4264:   PetscFunctionReturn(PETSC_SUCCESS);
4265: }

4267: /*@
4268:   MatCopy - Copies a matrix to another matrix.

4270:   Collective

4272:   Input Parameters:
4273: + A   - the matrix
4274: - str - `SAME_NONZERO_PATTERN` or `DIFFERENT_NONZERO_PATTERN`

4276:   Output Parameter:
4277: . B - where the copy is put

4279:   Level: intermediate

4281:   Notes:
4282:   If you use `SAME_NONZERO_PATTERN`, then the two matrices must have the same nonzero pattern or the routine will crash.

4284:   `MatCopy()` copies the matrix entries of a matrix to another existing
4285:   matrix (after first zeroing the second matrix).  A related routine is
4286:   `MatConvert()`, which first creates a new matrix and then copies the data.

4288: .seealso: [](ch_matrices), `Mat`, `MatConvert()`, `MatDuplicate()`
4289: @*/
4290: PetscErrorCode MatCopy(Mat A, Mat B, MatStructure str)
4291: {
4292:   PetscInt i;

4294:   PetscFunctionBegin;
4299:   PetscCheckSameComm(A, 1, B, 2);
4300:   MatCheckPreallocated(B, 2);
4301:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
4302:   PetscCheck(!A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4303:   PetscCheck(A->rmap->N == B->rmap->N && A->cmap->N == B->cmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat B: global dim (%" PetscInt_FMT ",%" PetscInt_FMT ") (%" PetscInt_FMT ",%" PetscInt_FMT ")", A->rmap->N, B->rmap->N,
4304:              A->cmap->N, B->cmap->N);
4305:   MatCheckPreallocated(A, 1);
4306:   if (A == B) PetscFunctionReturn(PETSC_SUCCESS);

4308:   PetscCall(PetscLogEventBegin(MAT_Copy, A, B, 0, 0));
4309:   if (A->ops->copy) PetscUseTypeMethod(A, copy, B, str);
4310:   else PetscCall(MatCopy_Basic(A, B, str));

4312:   B->stencil.dim = A->stencil.dim;
4313:   B->stencil.noc = A->stencil.noc;
4314:   for (i = 0; i <= A->stencil.dim + (A->stencil.noc ? 0 : -1); i++) {
4315:     B->stencil.dims[i]   = A->stencil.dims[i];
4316:     B->stencil.starts[i] = A->stencil.starts[i];
4317:   }

4319:   PetscCall(PetscLogEventEnd(MAT_Copy, A, B, 0, 0));
4320:   PetscCall(PetscObjectStateIncrease((PetscObject)B));
4321:   PetscFunctionReturn(PETSC_SUCCESS);
4322: }

4324: /*@
4325:   MatConvert - Converts a matrix to another matrix, either of the same
4326:   or different type.

4328:   Collective

4330:   Input Parameters:
4331: + mat     - the matrix
4332: . newtype - new matrix type.  Use `MATSAME` to create a new matrix of the
4333:             same type as the original matrix.
4334: - reuse   - denotes if the destination matrix is to be created or reused.
4335:             Use `MAT_INPLACE_MATRIX` for inplace conversion (that is when you want the input `Mat` to be changed to contain the matrix in the new format), otherwise use
4336:             `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX` (can only be used after the first call was made with `MAT_INITIAL_MATRIX`, causes the matrix space in M to be reused).

4338:   Output Parameter:
4339: . M - pointer to place new matrix

4341:   Level: intermediate

4343:   Notes:
4344:   `MatConvert()` first creates a new matrix and then copies the data from
4345:   the first matrix.  A related routine is `MatCopy()`, which copies the matrix
4346:   entries of one matrix to another already existing matrix context.

4348:   Cannot be used to convert a sequential matrix to parallel or parallel to sequential,
4349:   the MPI communicator of the generated matrix is always the same as the communicator
4350:   of the input matrix.

4352: .seealso: [](ch_matrices), `Mat`, `MatCopy()`, `MatDuplicate()`, `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, `MAT_INPLACE_MATRIX`
4353: @*/
4354: PetscErrorCode MatConvert(Mat mat, MatType newtype, MatReuse reuse, Mat *M)
4355: {
4356:   PetscBool  sametype, issame, flg;
4357:   PetscBool3 issymmetric, ishermitian;
4358:   char       convname[256], mtype[256];
4359:   Mat        B;

4361:   PetscFunctionBegin;
4364:   PetscAssertPointer(M, 4);
4365:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
4366:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4367:   MatCheckPreallocated(mat, 1);

4369:   PetscCall(PetscOptionsGetString(((PetscObject)mat)->options, ((PetscObject)mat)->prefix, "-matconvert_type", mtype, sizeof(mtype), &flg));
4370:   if (flg) newtype = mtype;

4372:   PetscCall(PetscObjectTypeCompare((PetscObject)mat, newtype, &sametype));
4373:   PetscCall(PetscStrcmp(newtype, "same", &issame));
4374:   PetscCheck(!(reuse == MAT_INPLACE_MATRIX) || !(mat != *M), PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "MAT_INPLACE_MATRIX requires same input and output matrix");
4375:   if (reuse == MAT_REUSE_MATRIX) {
4377:     PetscCheck(mat != *M, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "MAT_REUSE_MATRIX means reuse matrix in final argument, perhaps you mean MAT_INPLACE_MATRIX");
4378:   }

4380:   if ((reuse == MAT_INPLACE_MATRIX) && (issame || sametype)) {
4381:     PetscCall(PetscInfo(mat, "Early return for inplace %s %d %d\n", ((PetscObject)mat)->type_name, sametype, issame));
4382:     PetscFunctionReturn(PETSC_SUCCESS);
4383:   }

4385:   /* Cache Mat options because some converters use MatHeaderReplace  */
4386:   issymmetric = mat->symmetric;
4387:   ishermitian = mat->hermitian;

4389:   if ((sametype || issame) && (reuse == MAT_INITIAL_MATRIX) && mat->ops->duplicate) {
4390:     PetscCall(PetscInfo(mat, "Calling duplicate for initial matrix %s %d %d\n", ((PetscObject)mat)->type_name, sametype, issame));
4391:     PetscUseTypeMethod(mat, duplicate, MAT_COPY_VALUES, M);
4392:   } else {
4393:     PetscErrorCode (*conv)(Mat, MatType, MatReuse, Mat *) = NULL;
4394:     const char *prefix[3]                                 = {"seq", "mpi", ""};
4395:     PetscInt    i;
4396:     /*
4397:        Order of precedence:
4398:        0) See if newtype is a superclass of the current matrix.
4399:        1) See if a specialized converter is known to the current matrix.
4400:        2) See if a specialized converter is known to the desired matrix class.
4401:        3) See if a good general converter is registered for the desired class
4402:           (as of 6/27/03 only MATMPIADJ falls into this category).
4403:        4) See if a good general converter is known for the current matrix.
4404:        5) Use a really basic converter.
4405:     */

4407:     /* 0) See if newtype is a superclass of the current matrix.
4408:           i.e mat is mpiaij and newtype is aij */
4409:     for (i = 0; i < 2; i++) {
4410:       PetscCall(PetscStrncpy(convname, prefix[i], sizeof(convname)));
4411:       PetscCall(PetscStrlcat(convname, newtype, sizeof(convname)));
4412:       PetscCall(PetscStrcmp(convname, ((PetscObject)mat)->type_name, &flg));
4413:       PetscCall(PetscInfo(mat, "Check superclass %s %s -> %d\n", convname, ((PetscObject)mat)->type_name, flg));
4414:       if (flg) {
4415:         if (reuse == MAT_INPLACE_MATRIX) {
4416:           PetscCall(PetscInfo(mat, "Early return\n"));
4417:           PetscFunctionReturn(PETSC_SUCCESS);
4418:         } else if (reuse == MAT_INITIAL_MATRIX && mat->ops->duplicate) {
4419:           PetscCall(PetscInfo(mat, "Calling MatDuplicate\n"));
4420:           PetscUseTypeMethod(mat, duplicate, MAT_COPY_VALUES, M);
4421:           PetscFunctionReturn(PETSC_SUCCESS);
4422:         } else if (reuse == MAT_REUSE_MATRIX && mat->ops->copy) {
4423:           PetscCall(PetscInfo(mat, "Calling MatCopy\n"));
4424:           PetscCall(MatCopy(mat, *M, SAME_NONZERO_PATTERN));
4425:           PetscFunctionReturn(PETSC_SUCCESS);
4426:         }
4427:       }
4428:     }
4429:     /* 1) See if a specialized converter is known to the current matrix and the desired class */
4430:     for (i = 0; i < 3; i++) {
4431:       PetscCall(PetscStrncpy(convname, "MatConvert_", sizeof(convname)));
4432:       PetscCall(PetscStrlcat(convname, ((PetscObject)mat)->type_name, sizeof(convname)));
4433:       PetscCall(PetscStrlcat(convname, "_", sizeof(convname)));
4434:       PetscCall(PetscStrlcat(convname, prefix[i], sizeof(convname)));
4435:       PetscCall(PetscStrlcat(convname, issame ? ((PetscObject)mat)->type_name : newtype, sizeof(convname)));
4436:       PetscCall(PetscStrlcat(convname, "_C", sizeof(convname)));
4437:       PetscCall(PetscObjectQueryFunction((PetscObject)mat, convname, &conv));
4438:       PetscCall(PetscInfo(mat, "Check specialized (1) %s (%s) -> %d\n", convname, ((PetscObject)mat)->type_name, !!conv));
4439:       if (conv) goto foundconv;
4440:     }

4442:     /* 2)  See if a specialized converter is known to the desired matrix class. */
4443:     PetscCall(MatCreate(PetscObjectComm((PetscObject)mat), &B));
4444:     PetscCall(MatSetSizes(B, mat->rmap->n, mat->cmap->n, mat->rmap->N, mat->cmap->N));
4445:     PetscCall(MatSetType(B, newtype));
4446:     for (i = 0; i < 3; i++) {
4447:       PetscCall(PetscStrncpy(convname, "MatConvert_", sizeof(convname)));
4448:       PetscCall(PetscStrlcat(convname, ((PetscObject)mat)->type_name, sizeof(convname)));
4449:       PetscCall(PetscStrlcat(convname, "_", sizeof(convname)));
4450:       PetscCall(PetscStrlcat(convname, prefix[i], sizeof(convname)));
4451:       PetscCall(PetscStrlcat(convname, newtype, sizeof(convname)));
4452:       PetscCall(PetscStrlcat(convname, "_C", sizeof(convname)));
4453:       PetscCall(PetscObjectQueryFunction((PetscObject)B, convname, &conv));
4454:       PetscCall(PetscInfo(mat, "Check specialized (2) %s (%s) -> %d\n", convname, ((PetscObject)B)->type_name, !!conv));
4455:       if (conv) {
4456:         PetscCall(MatDestroy(&B));
4457:         goto foundconv;
4458:       }
4459:     }

4461:     /* 3) See if a good general converter is registered for the desired class */
4462:     conv = B->ops->convertfrom;
4463:     PetscCall(PetscInfo(mat, "Check convertfrom (%s) -> %d\n", ((PetscObject)B)->type_name, !!conv));
4464:     PetscCall(MatDestroy(&B));
4465:     if (conv) goto foundconv;

4467:     /* 4) See if a good general converter is known for the current matrix */
4468:     if (mat->ops->convert) conv = mat->ops->convert;
4469:     PetscCall(PetscInfo(mat, "Check general convert (%s) -> %d\n", ((PetscObject)mat)->type_name, !!conv));
4470:     if (conv) goto foundconv;

4472:     /* 5) Use a really basic converter. */
4473:     PetscCall(PetscInfo(mat, "Using MatConvert_Basic\n"));
4474:     conv = MatConvert_Basic;

4476:   foundconv:
4477:     PetscCall(PetscLogEventBegin(MAT_Convert, mat, 0, 0, 0));
4478:     PetscCall((*conv)(mat, newtype, reuse, M));
4479:     if (mat->rmap->mapping && mat->cmap->mapping && !(*M)->rmap->mapping && !(*M)->cmap->mapping) {
4480:       /* the block sizes must be same if the mappings are copied over */
4481:       (*M)->rmap->bs = mat->rmap->bs;
4482:       (*M)->cmap->bs = mat->cmap->bs;
4483:       PetscCall(PetscObjectReference((PetscObject)mat->rmap->mapping));
4484:       PetscCall(PetscObjectReference((PetscObject)mat->cmap->mapping));
4485:       (*M)->rmap->mapping = mat->rmap->mapping;
4486:       (*M)->cmap->mapping = mat->cmap->mapping;
4487:     }
4488:     (*M)->stencil.dim = mat->stencil.dim;
4489:     (*M)->stencil.noc = mat->stencil.noc;
4490:     for (i = 0; i <= mat->stencil.dim + (mat->stencil.noc ? 0 : -1); i++) {
4491:       (*M)->stencil.dims[i]   = mat->stencil.dims[i];
4492:       (*M)->stencil.starts[i] = mat->stencil.starts[i];
4493:     }
4494:     PetscCall(PetscLogEventEnd(MAT_Convert, mat, 0, 0, 0));
4495:   }
4496:   PetscCall(PetscObjectStateIncrease((PetscObject)*M));

4498:   /* Copy Mat options */
4499:   if (issymmetric == PETSC_BOOL3_TRUE) PetscCall(MatSetOption(*M, MAT_SYMMETRIC, PETSC_TRUE));
4500:   else if (issymmetric == PETSC_BOOL3_FALSE) PetscCall(MatSetOption(*M, MAT_SYMMETRIC, PETSC_FALSE));
4501:   if (ishermitian == PETSC_BOOL3_TRUE) PetscCall(MatSetOption(*M, MAT_HERMITIAN, PETSC_TRUE));
4502:   else if (ishermitian == PETSC_BOOL3_FALSE) PetscCall(MatSetOption(*M, MAT_HERMITIAN, PETSC_FALSE));
4503:   PetscFunctionReturn(PETSC_SUCCESS);
4504: }

4506: /*@
4507:   MatFactorGetSolverType - Returns name of the package providing the factorization routines

4509:   Not Collective

4511:   Input Parameter:
4512: . mat - the matrix, must be a factored matrix

4514:   Output Parameter:
4515: . type - the string name of the package (do not free this string)

4517:   Level: intermediate

4519:   Fortran Note:
4520:   Pass in an empty string that is long enough and the package name will be copied into it.

4522: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatSolverType`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`
4523: @*/
4524: PetscErrorCode MatFactorGetSolverType(Mat mat, MatSolverType *type)
4525: {
4526:   PetscErrorCode (*conv)(Mat, MatSolverType *);

4528:   PetscFunctionBegin;
4531:   PetscAssertPointer(type, 2);
4532:   PetscCheck(mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Only for factored matrix");
4533:   PetscCall(PetscObjectQueryFunction((PetscObject)mat, "MatFactorGetSolverType_C", &conv));
4534:   if (conv) PetscCall((*conv)(mat, type));
4535:   else *type = MATSOLVERPETSC;
4536:   PetscFunctionReturn(PETSC_SUCCESS);
4537: }

4539: typedef struct _MatSolverTypeForSpecifcType *MatSolverTypeForSpecifcType;
4540: struct _MatSolverTypeForSpecifcType {
4541:   MatType mtype;
4542:   /* no entry for MAT_FACTOR_NONE */
4543:   PetscErrorCode (*createfactor[MAT_FACTOR_NUM_TYPES - 1])(Mat, MatFactorType, Mat *);
4544:   MatSolverTypeForSpecifcType next;
4545: };

4547: typedef struct _MatSolverTypeHolder *MatSolverTypeHolder;
4548: struct _MatSolverTypeHolder {
4549:   char                       *name;
4550:   MatSolverTypeForSpecifcType handlers;
4551:   MatSolverTypeHolder         next;
4552: };

4554: static MatSolverTypeHolder MatSolverTypeHolders = NULL;

4556: /*@C
4557:   MatSolverTypeRegister - Registers a `MatSolverType` that works for a particular matrix type

4559:   Logically Collective, No Fortran Support

4561:   Input Parameters:
4562: + package      - name of the package, for example petsc or superlu
4563: . mtype        - the matrix type that works with this package
4564: . ftype        - the type of factorization supported by the package
4565: - createfactor - routine that will create the factored matrix ready to be used

4567:   Level: developer

4569: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorGetSolverType()`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`,
4570:   `MatGetFactor()`
4571: @*/
4572: PetscErrorCode MatSolverTypeRegister(MatSolverType package, MatType mtype, MatFactorType ftype, PetscErrorCode (*createfactor)(Mat, MatFactorType, Mat *))
4573: {
4574:   MatSolverTypeHolder         next = MatSolverTypeHolders, prev = NULL;
4575:   PetscBool                   flg;
4576:   MatSolverTypeForSpecifcType inext, iprev = NULL;

4578:   PetscFunctionBegin;
4579:   PetscCall(MatInitializePackage());
4580:   if (!next) {
4581:     PetscCall(PetscNew(&MatSolverTypeHolders));
4582:     PetscCall(PetscStrallocpy(package, &MatSolverTypeHolders->name));
4583:     PetscCall(PetscNew(&MatSolverTypeHolders->handlers));
4584:     PetscCall(PetscStrallocpy(mtype, (char **)&MatSolverTypeHolders->handlers->mtype));
4585:     MatSolverTypeHolders->handlers->createfactor[(int)ftype - 1] = createfactor;
4586:     PetscFunctionReturn(PETSC_SUCCESS);
4587:   }
4588:   while (next) {
4589:     PetscCall(PetscStrcasecmp(package, next->name, &flg));
4590:     if (flg) {
4591:       PetscCheck(next->handlers, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MatSolverTypeHolder is missing handlers");
4592:       inext = next->handlers;
4593:       while (inext) {
4594:         PetscCall(PetscStrcasecmp(mtype, inext->mtype, &flg));
4595:         if (flg) {
4596:           inext->createfactor[(int)ftype - 1] = createfactor;
4597:           PetscFunctionReturn(PETSC_SUCCESS);
4598:         }
4599:         iprev = inext;
4600:         inext = inext->next;
4601:       }
4602:       PetscCall(PetscNew(&iprev->next));
4603:       PetscCall(PetscStrallocpy(mtype, (char **)&iprev->next->mtype));
4604:       iprev->next->createfactor[(int)ftype - 1] = createfactor;
4605:       PetscFunctionReturn(PETSC_SUCCESS);
4606:     }
4607:     prev = next;
4608:     next = next->next;
4609:   }
4610:   PetscCall(PetscNew(&prev->next));
4611:   PetscCall(PetscStrallocpy(package, &prev->next->name));
4612:   PetscCall(PetscNew(&prev->next->handlers));
4613:   PetscCall(PetscStrallocpy(mtype, (char **)&prev->next->handlers->mtype));
4614:   prev->next->handlers->createfactor[(int)ftype - 1] = createfactor;
4615:   PetscFunctionReturn(PETSC_SUCCESS);
4616: }

4618: /*@C
4619:   MatSolverTypeGet - Gets the function that creates the factor matrix if it exist

4621:   Input Parameters:
4622: + type  - name of the package, for example petsc or superlu, if this is 'NULL', then the first result that satisfies the other criteria is returned
4623: . ftype - the type of factorization supported by the type
4624: - mtype - the matrix type that works with this type

4626:   Output Parameters:
4627: + foundtype    - `PETSC_TRUE` if the type was registered
4628: . foundmtype   - `PETSC_TRUE` if the type supports the requested mtype
4629: - createfactor - routine that will create the factored matrix ready to be used or `NULL` if not found

4631:   Calling sequence of `createfactor`:
4632: + A     - the matrix providing the factor matrix
4633: . ftype - the `MatFactorType` of the factor requested
4634: - B     - the new factor matrix that responds to MatXXFactorSymbolic,Numeric() functions, such as `MatLUFactorSymbolic()`

4636:   Level: developer

4638:   Note:
4639:   When `type` is `NULL` the available functions are searched for based on the order of the calls to `MatSolverTypeRegister()` in `MatInitializePackage()`.
4640:   Since different PETSc configurations may have different external solvers, seemingly identical runs with different PETSc configurations may use a different solver.
4641:   For example if one configuration had `--download-mumps` while a different one had `--download-superlu_dist`.

4643: .seealso: [](ch_matrices), `Mat`, `MatFactorType`, `MatType`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`, `MatSolverTypeRegister()`, `MatGetFactor()`,
4644:           `MatInitializePackage()`
4645: @*/
4646: PetscErrorCode MatSolverTypeGet(MatSolverType type, MatType mtype, MatFactorType ftype, PetscBool *foundtype, PetscBool *foundmtype, PetscErrorCode (**createfactor)(Mat A, MatFactorType ftype, Mat *B))
4647: {
4648:   MatSolverTypeHolder         next = MatSolverTypeHolders;
4649:   PetscBool                   flg;
4650:   MatSolverTypeForSpecifcType inext;

4652:   PetscFunctionBegin;
4653:   if (foundtype) *foundtype = PETSC_FALSE;
4654:   if (foundmtype) *foundmtype = PETSC_FALSE;
4655:   if (createfactor) *createfactor = NULL;

4657:   if (type) {
4658:     while (next) {
4659:       PetscCall(PetscStrcasecmp(type, next->name, &flg));
4660:       if (flg) {
4661:         if (foundtype) *foundtype = PETSC_TRUE;
4662:         inext = next->handlers;
4663:         while (inext) {
4664:           PetscCall(PetscStrbeginswith(mtype, inext->mtype, &flg));
4665:           if (flg) {
4666:             if (foundmtype) *foundmtype = PETSC_TRUE;
4667:             if (createfactor) *createfactor = inext->createfactor[(int)ftype - 1];
4668:             PetscFunctionReturn(PETSC_SUCCESS);
4669:           }
4670:           inext = inext->next;
4671:         }
4672:       }
4673:       next = next->next;
4674:     }
4675:   } else {
4676:     while (next) {
4677:       inext = next->handlers;
4678:       while (inext) {
4679:         PetscCall(PetscStrcmp(mtype, inext->mtype, &flg));
4680:         if (flg && inext->createfactor[(int)ftype - 1]) {
4681:           if (foundtype) *foundtype = PETSC_TRUE;
4682:           if (foundmtype) *foundmtype = PETSC_TRUE;
4683:           if (createfactor) *createfactor = inext->createfactor[(int)ftype - 1];
4684:           PetscFunctionReturn(PETSC_SUCCESS);
4685:         }
4686:         inext = inext->next;
4687:       }
4688:       next = next->next;
4689:     }
4690:     /* try with base classes inext->mtype */
4691:     next = MatSolverTypeHolders;
4692:     while (next) {
4693:       inext = next->handlers;
4694:       while (inext) {
4695:         PetscCall(PetscStrbeginswith(mtype, inext->mtype, &flg));
4696:         if (flg && inext->createfactor[(int)ftype - 1]) {
4697:           if (foundtype) *foundtype = PETSC_TRUE;
4698:           if (foundmtype) *foundmtype = PETSC_TRUE;
4699:           if (createfactor) *createfactor = inext->createfactor[(int)ftype - 1];
4700:           PetscFunctionReturn(PETSC_SUCCESS);
4701:         }
4702:         inext = inext->next;
4703:       }
4704:       next = next->next;
4705:     }
4706:   }
4707:   PetscFunctionReturn(PETSC_SUCCESS);
4708: }

4710: PetscErrorCode MatSolverTypeDestroy(void)
4711: {
4712:   MatSolverTypeHolder         next = MatSolverTypeHolders, prev;
4713:   MatSolverTypeForSpecifcType inext, iprev;

4715:   PetscFunctionBegin;
4716:   while (next) {
4717:     PetscCall(PetscFree(next->name));
4718:     inext = next->handlers;
4719:     while (inext) {
4720:       PetscCall(PetscFree(inext->mtype));
4721:       iprev = inext;
4722:       inext = inext->next;
4723:       PetscCall(PetscFree(iprev));
4724:     }
4725:     prev = next;
4726:     next = next->next;
4727:     PetscCall(PetscFree(prev));
4728:   }
4729:   MatSolverTypeHolders = NULL;
4730:   PetscFunctionReturn(PETSC_SUCCESS);
4731: }

4733: /*@
4734:   MatFactorGetCanUseOrdering - Indicates if the factorization can use the ordering provided in `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`

4736:   Logically Collective

4738:   Input Parameter:
4739: . mat - the matrix

4741:   Output Parameter:
4742: . flg - `PETSC_TRUE` if uses the ordering

4744:   Level: developer

4746:   Note:
4747:   Most internal PETSc factorizations use the ordering passed to the factorization routine but external
4748:   packages do not, thus we want to skip generating the ordering when it is not needed or used.

4750: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`
4751: @*/
4752: PetscErrorCode MatFactorGetCanUseOrdering(Mat mat, PetscBool *flg)
4753: {
4754:   PetscFunctionBegin;
4755:   *flg = mat->canuseordering;
4756:   PetscFunctionReturn(PETSC_SUCCESS);
4757: }

4759: /*@
4760:   MatFactorGetPreferredOrdering - The preferred ordering for a particular matrix factor object

4762:   Logically Collective

4764:   Input Parameters:
4765: + mat   - the matrix obtained with `MatGetFactor()`
4766: - ftype - the factorization type to be used

4768:   Output Parameter:
4769: . otype - the preferred ordering type

4771:   Level: developer

4773: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorType`, `MatOrderingType`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`
4774: @*/
4775: PetscErrorCode MatFactorGetPreferredOrdering(Mat mat, MatFactorType ftype, MatOrderingType *otype)
4776: {
4777:   PetscFunctionBegin;
4778:   *otype = mat->preferredordering[ftype];
4779:   PetscCheck(*otype, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MatFactor did not have a preferred ordering");
4780:   PetscFunctionReturn(PETSC_SUCCESS);
4781: }

4783: /*@
4784:   MatGetFactor - Returns a matrix suitable to calls to MatXXFactorSymbolic,Numeric()

4786:   Collective

4788:   Input Parameters:
4789: + mat   - the matrix
4790: . type  - name of solver type, for example, superlu, petsc (to use PETSc's solver if it is available), if this is 'NULL', then the first result that satisfies
4791:           the other criteria is returned
4792: - ftype - factor type, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`

4794:   Output Parameter:
4795: . f - the factor matrix used with MatXXFactorSymbolic,Numeric() calls. Can be `NULL` in some cases, see notes below.

4797:   Options Database Keys:
4798: + -pc_factor_mat_solver_type <type>             - choose the type at run time. When using `KSP` solvers
4799: - -mat_factor_bind_factorization <host, device> - Where to do matrix factorization? Default is device (might consume more device memory.
4800:                                                   One can choose host to save device memory). Currently only supported with `MATSEQAIJCUSPARSE` matrices.

4802:   Level: intermediate

4804:   Notes:
4805:   The return matrix can be `NULL` if the requested factorization is not available, since some combinations of matrix types and factorization
4806:   types registered with `MatSolverTypeRegister()` cannot be fully tested if not at runtime.

4808:   Users usually access the factorization solvers via `KSP`

4810:   Some PETSc matrix formats have alternative solvers available that are contained in alternative packages
4811:   such as pastix, superlu, mumps etc. PETSc must have been ./configure to use the external solver, using the option --download-package or --with-package-dir

4813:   When `type` is `NULL` the available results are searched for based on the order of the calls to `MatSolverTypeRegister()` in `MatInitializePackage()`.
4814:   Since different PETSc configurations may have different external solvers, seemingly identical runs with different PETSc configurations may use a different solver.
4815:   For example if one configuration had --download-mumps while a different one had --download-superlu_dist.

4817:   Some of the packages have options for controlling the factorization, these are in the form -prefix_mat_packagename_packageoption
4818:   where prefix is normally obtained from the calling `KSP`/`PC`. If `MatGetFactor()` is called directly one can set
4819:   call `MatSetOptionsPrefixFactor()` on the originating matrix or  `MatSetOptionsPrefix()` on the resulting factor matrix.

4821:   Developer Note:
4822:   This should actually be called `MatCreateFactor()` since it creates a new factor object

4824: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `KSP`, `MatSolverType`, `MatFactorType`, `MatCopy()`, `MatDuplicate()`,
4825:           `MatGetFactorAvailable()`, `MatFactorGetCanUseOrdering()`, `MatSolverTypeRegister()`, `MatSolverTypeGet()`
4826:           `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`, `MatInitializePackage()`
4827: @*/
4828: PetscErrorCode MatGetFactor(Mat mat, MatSolverType type, MatFactorType ftype, Mat *f)
4829: {
4830:   PetscBool foundtype, foundmtype, shell, hasop = PETSC_FALSE;
4831:   PetscErrorCode (*conv)(Mat, MatFactorType, Mat *);

4833:   PetscFunctionBegin;

4837:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4838:   MatCheckPreallocated(mat, 1);

4840:   PetscCall(MatIsShell(mat, &shell));
4841:   if (shell) PetscCall(MatHasOperation(mat, MATOP_GET_FACTOR, &hasop));
4842:   if (hasop) {
4843:     PetscUseTypeMethod(mat, getfactor, type, ftype, f);
4844:     PetscFunctionReturn(PETSC_SUCCESS);
4845:   }

4847:   PetscCall(MatSolverTypeGet(type, ((PetscObject)mat)->type_name, ftype, &foundtype, &foundmtype, &conv));
4848:   if (!foundtype) {
4849:     if (type) {
4850:       SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_MISSING_FACTOR, "Could not locate solver type %s for factorization type %s and matrix type %s. Perhaps you must ./configure with --download-%s", type, MatFactorTypes[ftype],
4851:               ((PetscObject)mat)->type_name, type);
4852:     } else {
4853:       SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_MISSING_FACTOR, "Could not locate a solver type for factorization type %s and matrix type %s.", MatFactorTypes[ftype], ((PetscObject)mat)->type_name);
4854:     }
4855:   }
4856:   PetscCheck(foundmtype, PetscObjectComm((PetscObject)mat), PETSC_ERR_MISSING_FACTOR, "MatSolverType %s does not support matrix type %s", type, ((PetscObject)mat)->type_name);
4857:   PetscCheck(conv, PetscObjectComm((PetscObject)mat), PETSC_ERR_MISSING_FACTOR, "MatSolverType %s does not support factorization type %s for matrix type %s", type, MatFactorTypes[ftype], ((PetscObject)mat)->type_name);

4859:   PetscCall((*conv)(mat, ftype, f));
4860:   if (mat->factorprefix) PetscCall(MatSetOptionsPrefix(*f, mat->factorprefix));
4861:   PetscFunctionReturn(PETSC_SUCCESS);
4862: }

4864: /*@
4865:   MatGetFactorAvailable - Returns a flag if matrix supports particular type and factor type

4867:   Not Collective

4869:   Input Parameters:
4870: + mat   - the matrix
4871: . type  - name of solver type, for example, superlu, petsc (to use PETSc's default)
4872: - ftype - factor type, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`

4874:   Output Parameter:
4875: . flg - PETSC_TRUE if the factorization is available

4877:   Level: intermediate

4879:   Notes:
4880:   Some PETSc matrix formats have alternative solvers available that are contained in alternative packages
4881:   such as pastix, superlu, mumps etc.

4883:   PETSc must have been ./configure to use the external solver, using the option --download-package

4885:   Developer Note:
4886:   This should actually be called `MatCreateFactorAvailable()` since `MatGetFactor()` creates a new factor object

4888: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatSolverType`, `MatFactorType`, `MatGetFactor()`, `MatCopy()`, `MatDuplicate()`, `MatSolverTypeRegister()`,
4889:           `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`, `MatSolverTypeGet()`
4890: @*/
4891: PetscErrorCode MatGetFactorAvailable(Mat mat, MatSolverType type, MatFactorType ftype, PetscBool *flg)
4892: {
4893:   PetscErrorCode (*gconv)(Mat, MatFactorType, Mat *);

4895:   PetscFunctionBegin;
4897:   PetscAssertPointer(flg, 4);

4899:   *flg = PETSC_FALSE;
4900:   if (!((PetscObject)mat)->type_name) PetscFunctionReturn(PETSC_SUCCESS);

4902:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4903:   MatCheckPreallocated(mat, 1);

4905:   PetscCall(MatSolverTypeGet(type, ((PetscObject)mat)->type_name, ftype, NULL, NULL, &gconv));
4906:   *flg = gconv ? PETSC_TRUE : PETSC_FALSE;
4907:   PetscFunctionReturn(PETSC_SUCCESS);
4908: }

4910: /*@
4911:   MatDuplicate - Duplicates a matrix including the non-zero structure.

4913:   Collective

4915:   Input Parameters:
4916: + mat - the matrix
4917: - op  - One of `MAT_DO_NOT_COPY_VALUES`, `MAT_COPY_VALUES`, or `MAT_SHARE_NONZERO_PATTERN`.
4918:         See the manual page for `MatDuplicateOption()` for an explanation of these options.

4920:   Output Parameter:
4921: . M - pointer to place new matrix

4923:   Level: intermediate

4925:   Notes:
4926:   You cannot change the nonzero pattern for the parent or child matrix later if you use `MAT_SHARE_NONZERO_PATTERN`.

4928:   If `op` is not `MAT_COPY_VALUES` the numerical values in the new matrix are zeroed.

4930:   May be called with an unassembled input `Mat` if `MAT_DO_NOT_COPY_VALUES` is used, in which case the output `Mat` is unassembled as well.

4932:   When original mat is a product of matrix operation, e.g., an output of `MatMatMult()` or `MatCreateSubMatrix()`, only the matrix data structure of `mat`
4933:   is duplicated and the internal data structures created for the reuse of previous matrix operations are not duplicated.
4934:   User should not use `MatDuplicate()` to create new matrix `M` if `M` is intended to be reused as the product of matrix operation.

4936: .seealso: [](ch_matrices), `Mat`, `MatCopy()`, `MatConvert()`, `MatDuplicateOption`
4937: @*/
4938: PetscErrorCode MatDuplicate(Mat mat, MatDuplicateOption op, Mat *M)
4939: {
4940:   Mat         B;
4941:   VecType     vtype;
4942:   PetscInt    i;
4943:   PetscObject dm, container_h, container_d;
4944:   void (*viewf)(void);

4946:   PetscFunctionBegin;
4949:   PetscAssertPointer(M, 3);
4950:   PetscCheck(op != MAT_COPY_VALUES || mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "MAT_COPY_VALUES not allowed for unassembled matrix");
4951:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4952:   MatCheckPreallocated(mat, 1);

4954:   *M = NULL;
4955:   PetscCall(PetscLogEventBegin(MAT_Convert, mat, 0, 0, 0));
4956:   PetscUseTypeMethod(mat, duplicate, op, M);
4957:   PetscCall(PetscLogEventEnd(MAT_Convert, mat, 0, 0, 0));
4958:   B = *M;

4960:   PetscCall(MatGetOperation(mat, MATOP_VIEW, &viewf));
4961:   if (viewf) PetscCall(MatSetOperation(B, MATOP_VIEW, viewf));
4962:   PetscCall(MatGetVecType(mat, &vtype));
4963:   PetscCall(MatSetVecType(B, vtype));

4965:   B->stencil.dim = mat->stencil.dim;
4966:   B->stencil.noc = mat->stencil.noc;
4967:   for (i = 0; i <= mat->stencil.dim + (mat->stencil.noc ? 0 : -1); i++) {
4968:     B->stencil.dims[i]   = mat->stencil.dims[i];
4969:     B->stencil.starts[i] = mat->stencil.starts[i];
4970:   }

4972:   B->nooffproczerorows = mat->nooffproczerorows;
4973:   B->nooffprocentries  = mat->nooffprocentries;

4975:   PetscCall(PetscObjectQuery((PetscObject)mat, "__PETSc_dm", &dm));
4976:   if (dm) PetscCall(PetscObjectCompose((PetscObject)B, "__PETSc_dm", dm));
4977:   PetscCall(PetscObjectQuery((PetscObject)mat, "__PETSc_MatCOOStruct_Host", &container_h));
4978:   if (container_h) PetscCall(PetscObjectCompose((PetscObject)B, "__PETSc_MatCOOStruct_Host", container_h));
4979:   PetscCall(PetscObjectQuery((PetscObject)mat, "__PETSc_MatCOOStruct_Device", &container_d));
4980:   if (container_d) PetscCall(PetscObjectCompose((PetscObject)B, "__PETSc_MatCOOStruct_Device", container_d));
4981:   if (op == MAT_COPY_VALUES) PetscCall(MatPropagateSymmetryOptions(mat, B));
4982:   PetscCall(PetscObjectStateIncrease((PetscObject)B));
4983:   PetscFunctionReturn(PETSC_SUCCESS);
4984: }

4986: /*@
4987:   MatGetDiagonal - Gets the diagonal of a matrix as a `Vec`

4989:   Logically Collective

4991:   Input Parameter:
4992: . mat - the matrix

4994:   Output Parameter:
4995: . v - the diagonal of the matrix

4997:   Level: intermediate

4999:   Note:
5000:   If `mat` has local sizes `n` x `m`, this routine fills the first `ndiag = min(n, m)` entries
5001:   of `v` with the diagonal values. Thus `v` must have local size of at least `ndiag`. If `v`
5002:   is larger than `ndiag`, the values of the remaining entries are unspecified.

5004:   Currently only correct in parallel for square matrices.

5006: .seealso: [](ch_matrices), `Mat`, `Vec`, `MatGetRow()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMaxAbs()`
5007: @*/
5008: PetscErrorCode MatGetDiagonal(Mat mat, Vec v)
5009: {
5010:   PetscFunctionBegin;
5014:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5015:   MatCheckPreallocated(mat, 1);
5016:   if (PetscDefined(USE_DEBUG)) {
5017:     PetscInt nv, row, col, ndiag;

5019:     PetscCall(VecGetLocalSize(v, &nv));
5020:     PetscCall(MatGetLocalSize(mat, &row, &col));
5021:     ndiag = PetscMin(row, col);
5022:     PetscCheck(nv >= ndiag, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Nonconforming Mat and Vec. Vec local size %" PetscInt_FMT " < Mat local diagonal length %" PetscInt_FMT, nv, ndiag);
5023:   }

5025:   PetscUseTypeMethod(mat, getdiagonal, v);
5026:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5027:   PetscFunctionReturn(PETSC_SUCCESS);
5028: }

5030: /*@
5031:   MatGetRowMin - Gets the minimum value (of the real part) of each
5032:   row of the matrix

5034:   Logically Collective

5036:   Input Parameter:
5037: . mat - the matrix

5039:   Output Parameters:
5040: + v   - the vector for storing the maximums
5041: - idx - the indices of the column found for each row (optional, pass `NULL` if not needed)

5043:   Level: intermediate

5045:   Note:
5046:   The result of this call are the same as if one converted the matrix to dense format
5047:   and found the minimum value in each row (i.e. the implicit zeros are counted as zeros).

5049:   This code is only implemented for a couple of matrix formats.

5051: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMaxAbs()`, `MatGetRowMinAbs()`,
5052:           `MatGetRowMax()`
5053: @*/
5054: PetscErrorCode MatGetRowMin(Mat mat, Vec v, PetscInt idx[])
5055: {
5056:   PetscFunctionBegin;
5060:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");

5062:   if (!mat->cmap->N) {
5063:     PetscCall(VecSet(v, PETSC_MAX_REAL));
5064:     if (idx) {
5065:       PetscInt i, m = mat->rmap->n;
5066:       for (i = 0; i < m; i++) idx[i] = -1;
5067:     }
5068:   } else {
5069:     MatCheckPreallocated(mat, 1);
5070:   }
5071:   PetscUseTypeMethod(mat, getrowmin, v, idx);
5072:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5073:   PetscFunctionReturn(PETSC_SUCCESS);
5074: }

5076: /*@
5077:   MatGetRowMinAbs - Gets the minimum value (in absolute value) of each
5078:   row of the matrix

5080:   Logically Collective

5082:   Input Parameter:
5083: . mat - the matrix

5085:   Output Parameters:
5086: + v   - the vector for storing the minimums
5087: - idx - the indices of the column found for each row (or `NULL` if not needed)

5089:   Level: intermediate

5091:   Notes:
5092:   if a row is completely empty or has only 0.0 values, then the `idx` value for that
5093:   row is 0 (the first column).

5095:   This code is only implemented for a couple of matrix formats.

5097: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMax()`, `MatGetRowMaxAbs()`, `MatGetRowMin()`
5098: @*/
5099: PetscErrorCode MatGetRowMinAbs(Mat mat, Vec v, PetscInt idx[])
5100: {
5101:   PetscFunctionBegin;
5105:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5106:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");

5108:   if (!mat->cmap->N) {
5109:     PetscCall(VecSet(v, 0.0));
5110:     if (idx) {
5111:       PetscInt i, m = mat->rmap->n;
5112:       for (i = 0; i < m; i++) idx[i] = -1;
5113:     }
5114:   } else {
5115:     MatCheckPreallocated(mat, 1);
5116:     if (idx) PetscCall(PetscArrayzero(idx, mat->rmap->n));
5117:     PetscUseTypeMethod(mat, getrowminabs, v, idx);
5118:   }
5119:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5120:   PetscFunctionReturn(PETSC_SUCCESS);
5121: }

5123: /*@
5124:   MatGetRowMax - Gets the maximum value (of the real part) of each
5125:   row of the matrix

5127:   Logically Collective

5129:   Input Parameter:
5130: . mat - the matrix

5132:   Output Parameters:
5133: + v   - the vector for storing the maximums
5134: - idx - the indices of the column found for each row (optional, otherwise pass `NULL`)

5136:   Level: intermediate

5138:   Notes:
5139:   The result of this call are the same as if one converted the matrix to dense format
5140:   and found the minimum value in each row (i.e. the implicit zeros are counted as zeros).

5142:   This code is only implemented for a couple of matrix formats.

5144: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMaxAbs()`, `MatGetRowMin()`, `MatGetRowMinAbs()`
5145: @*/
5146: PetscErrorCode MatGetRowMax(Mat mat, Vec v, PetscInt idx[])
5147: {
5148:   PetscFunctionBegin;
5152:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");

5154:   if (!mat->cmap->N) {
5155:     PetscCall(VecSet(v, PETSC_MIN_REAL));
5156:     if (idx) {
5157:       PetscInt i, m = mat->rmap->n;
5158:       for (i = 0; i < m; i++) idx[i] = -1;
5159:     }
5160:   } else {
5161:     MatCheckPreallocated(mat, 1);
5162:     PetscUseTypeMethod(mat, getrowmax, v, idx);
5163:   }
5164:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5165:   PetscFunctionReturn(PETSC_SUCCESS);
5166: }

5168: /*@
5169:   MatGetRowMaxAbs - Gets the maximum value (in absolute value) of each
5170:   row of the matrix

5172:   Logically Collective

5174:   Input Parameter:
5175: . mat - the matrix

5177:   Output Parameters:
5178: + v   - the vector for storing the maximums
5179: - idx - the indices of the column found for each row (or `NULL` if not needed)

5181:   Level: intermediate

5183:   Notes:
5184:   if a row is completely empty or has only 0.0 values, then the `idx` value for that
5185:   row is 0 (the first column).

5187:   This code is only implemented for a couple of matrix formats.

5189: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowSum()`, `MatGetRowMin()`, `MatGetRowMinAbs()`
5190: @*/
5191: PetscErrorCode MatGetRowMaxAbs(Mat mat, Vec v, PetscInt idx[])
5192: {
5193:   PetscFunctionBegin;
5197:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");

5199:   if (!mat->cmap->N) {
5200:     PetscCall(VecSet(v, 0.0));
5201:     if (idx) {
5202:       PetscInt i, m = mat->rmap->n;
5203:       for (i = 0; i < m; i++) idx[i] = -1;
5204:     }
5205:   } else {
5206:     MatCheckPreallocated(mat, 1);
5207:     if (idx) PetscCall(PetscArrayzero(idx, mat->rmap->n));
5208:     PetscUseTypeMethod(mat, getrowmaxabs, v, idx);
5209:   }
5210:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5211:   PetscFunctionReturn(PETSC_SUCCESS);
5212: }

5214: /*@
5215:   MatGetRowSumAbs - Gets the sum value (in absolute value) of each row of the matrix

5217:   Logically Collective

5219:   Input Parameter:
5220: . mat - the matrix

5222:   Output Parameter:
5223: . v - the vector for storing the sum

5225:   Level: intermediate

5227:   This code is only implemented for a couple of matrix formats.

5229: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMax()`, `MatGetRowMin()`, `MatGetRowMinAbs()`
5230: @*/
5231: PetscErrorCode MatGetRowSumAbs(Mat mat, Vec v)
5232: {
5233:   PetscFunctionBegin;
5237:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");

5239:   if (!mat->cmap->N) {
5240:     PetscCall(VecSet(v, 0.0));
5241:   } else {
5242:     MatCheckPreallocated(mat, 1);
5243:     PetscUseTypeMethod(mat, getrowsumabs, v);
5244:   }
5245:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5246:   PetscFunctionReturn(PETSC_SUCCESS);
5247: }

5249: /*@
5250:   MatGetRowSum - Gets the sum of each row of the matrix

5252:   Logically or Neighborhood Collective

5254:   Input Parameter:
5255: . mat - the matrix

5257:   Output Parameter:
5258: . v - the vector for storing the sum of rows

5260:   Level: intermediate

5262:   Note:
5263:   This code is slow since it is not currently specialized for different formats

5265: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMax()`, `MatGetRowMin()`, `MatGetRowMaxAbs()`, `MatGetRowMinAbs()`, `MatGetRowSumAbs()`
5266: @*/
5267: PetscErrorCode MatGetRowSum(Mat mat, Vec v)
5268: {
5269:   Vec ones;

5271:   PetscFunctionBegin;
5275:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5276:   MatCheckPreallocated(mat, 1);
5277:   PetscCall(MatCreateVecs(mat, &ones, NULL));
5278:   PetscCall(VecSet(ones, 1.));
5279:   PetscCall(MatMult(mat, ones, v));
5280:   PetscCall(VecDestroy(&ones));
5281:   PetscFunctionReturn(PETSC_SUCCESS);
5282: }

5284: /*@
5285:   MatTransposeSetPrecursor - Set the matrix from which the second matrix will receive numerical transpose data with a call to `MatTranspose`(A,`MAT_REUSE_MATRIX`,&B)
5286:   when B was not obtained with `MatTranspose`(A,`MAT_INITIAL_MATRIX`,&B)

5288:   Collective

5290:   Input Parameter:
5291: . mat - the matrix to provide the transpose

5293:   Output Parameter:
5294: . B - the matrix to contain the transpose; it MUST have the nonzero structure of the transpose of A or the code will crash or generate incorrect results

5296:   Level: advanced

5298:   Note:
5299:   Normally the use of `MatTranspose`(A, `MAT_REUSE_MATRIX`, &B) requires that `B` was obtained with a call to `MatTranspose`(A, `MAT_INITIAL_MATRIX`, &B). This
5300:   routine allows bypassing that call.

5302: .seealso: [](ch_matrices), `Mat`, `MatTransposeSymbolic()`, `MatTranspose()`, `MatMultTranspose()`, `MatMultTransposeAdd()`, `MatIsTranspose()`, `MatReuse`, `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, `MAT_INPLACE_MATRIX`
5303: @*/
5304: PetscErrorCode MatTransposeSetPrecursor(Mat mat, Mat B)
5305: {
5306:   MatParentState *rb = NULL;

5308:   PetscFunctionBegin;
5309:   PetscCall(PetscNew(&rb));
5310:   rb->id    = ((PetscObject)mat)->id;
5311:   rb->state = 0;
5312:   PetscCall(MatGetNonzeroState(mat, &rb->nonzerostate));
5313:   PetscCall(PetscObjectContainerCompose((PetscObject)B, "MatTransposeParent", rb, PetscContainerUserDestroyDefault));
5314:   PetscFunctionReturn(PETSC_SUCCESS);
5315: }

5317: /*@
5318:   MatTranspose - Computes the transpose of a matrix, either in-place or out-of-place.

5320:   Collective

5322:   Input Parameters:
5323: + mat   - the matrix to transpose
5324: - reuse - either `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, or `MAT_INPLACE_MATRIX`

5326:   Output Parameter:
5327: . B - the transpose of the matrix

5329:   Level: intermediate

5331:   Notes:
5332:   If you use `MAT_INPLACE_MATRIX` then you must pass in `&mat` for `B`

5334:   `MAT_REUSE_MATRIX` uses the `B` matrix obtained from a previous call to this function with `MAT_INITIAL_MATRIX` to store the transpose. If you already have a matrix to contain the
5335:   transpose, call `MatTransposeSetPrecursor(mat, B)` before calling this routine.

5337:   If the nonzero structure of `mat` changed from the previous call to this function with the same matrices an error will be generated for some matrix types.

5339:   Consider using `MatCreateTranspose()` instead if you only need a matrix that behaves like the transpose but don't need the storage to be changed.
5340:   For example, the result of `MatCreateTranspose()` will compute the transpose of the given matrix times a vector for matrix-vector products computed with `MatMult()`.

5342:   If `mat` is unchanged from the last call this function returns immediately without recomputing the result

5344:   If you only need the symbolic transpose of a matrix, and not the numerical values, use `MatTransposeSymbolic()`

5346: .seealso: [](ch_matrices), `Mat`, `MatTransposeSetPrecursor()`, `MatMultTranspose()`, `MatMultTransposeAdd()`, `MatIsTranspose()`, `MatReuse`, `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, `MAT_INPLACE_MATRIX`,
5347:           `MatTransposeSymbolic()`, `MatCreateTranspose()`
5348: @*/
5349: PetscErrorCode MatTranspose(Mat mat, MatReuse reuse, Mat *B)
5350: {
5351:   PetscContainer  rB = NULL;
5352:   MatParentState *rb = NULL;

5354:   PetscFunctionBegin;
5357:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5358:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5359:   PetscCheck(reuse != MAT_INPLACE_MATRIX || mat == *B, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "MAT_INPLACE_MATRIX requires last matrix to match first");
5360:   PetscCheck(reuse != MAT_REUSE_MATRIX || mat != *B, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Perhaps you mean MAT_INPLACE_MATRIX");
5361:   MatCheckPreallocated(mat, 1);
5362:   if (reuse == MAT_REUSE_MATRIX) {
5363:     PetscCall(PetscObjectQuery((PetscObject)*B, "MatTransposeParent", (PetscObject *)&rB));
5364:     PetscCheck(rB, PetscObjectComm((PetscObject)*B), PETSC_ERR_ARG_WRONG, "Reuse matrix used was not generated from call to MatTranspose(). Suggest MatTransposeSetPrecursor().");
5365:     PetscCall(PetscContainerGetPointer(rB, (void **)&rb));
5366:     PetscCheck(rb->id == ((PetscObject)mat)->id, PetscObjectComm((PetscObject)*B), PETSC_ERR_ARG_WRONG, "Reuse matrix used was not generated from input matrix");
5367:     if (rb->state == ((PetscObject)mat)->state) PetscFunctionReturn(PETSC_SUCCESS);
5368:   }

5370:   PetscCall(PetscLogEventBegin(MAT_Transpose, mat, 0, 0, 0));
5371:   if (reuse != MAT_INPLACE_MATRIX || mat->symmetric != PETSC_BOOL3_TRUE) {
5372:     PetscUseTypeMethod(mat, transpose, reuse, B);
5373:     PetscCall(PetscObjectStateIncrease((PetscObject)*B));
5374:   }
5375:   PetscCall(PetscLogEventEnd(MAT_Transpose, mat, 0, 0, 0));

5377:   if (reuse == MAT_INITIAL_MATRIX) PetscCall(MatTransposeSetPrecursor(mat, *B));
5378:   if (reuse != MAT_INPLACE_MATRIX) {
5379:     PetscCall(PetscObjectQuery((PetscObject)*B, "MatTransposeParent", (PetscObject *)&rB));
5380:     PetscCall(PetscContainerGetPointer(rB, (void **)&rb));
5381:     rb->state        = ((PetscObject)mat)->state;
5382:     rb->nonzerostate = mat->nonzerostate;
5383:   }
5384:   PetscFunctionReturn(PETSC_SUCCESS);
5385: }

5387: /*@
5388:   MatTransposeSymbolic - Computes the symbolic part of the transpose of a matrix.

5390:   Collective

5392:   Input Parameter:
5393: . A - the matrix to transpose

5395:   Output Parameter:
5396: . B - the transpose. This is a complete matrix but the numerical portion is invalid. One can call `MatTranspose`(A,`MAT_REUSE_MATRIX`,&B) to compute the
5397:       numerical portion.

5399:   Level: intermediate

5401:   Note:
5402:   This is not supported for many matrix types, use `MatTranspose()` in those cases

5404: .seealso: [](ch_matrices), `Mat`, `MatTransposeSetPrecursor()`, `MatTranspose()`, `MatMultTranspose()`, `MatMultTransposeAdd()`, `MatIsTranspose()`, `MatReuse`, `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, `MAT_INPLACE_MATRIX`
5405: @*/
5406: PetscErrorCode MatTransposeSymbolic(Mat A, Mat *B)
5407: {
5408:   PetscFunctionBegin;
5411:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5412:   PetscCheck(!A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5413:   PetscCall(PetscLogEventBegin(MAT_Transpose, A, 0, 0, 0));
5414:   PetscUseTypeMethod(A, transposesymbolic, B);
5415:   PetscCall(PetscLogEventEnd(MAT_Transpose, A, 0, 0, 0));

5417:   PetscCall(MatTransposeSetPrecursor(A, *B));
5418:   PetscFunctionReturn(PETSC_SUCCESS);
5419: }

5421: PetscErrorCode MatTransposeCheckNonzeroState_Private(Mat A, Mat B)
5422: {
5423:   PetscContainer  rB;
5424:   MatParentState *rb;

5426:   PetscFunctionBegin;
5429:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5430:   PetscCheck(!A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5431:   PetscCall(PetscObjectQuery((PetscObject)B, "MatTransposeParent", (PetscObject *)&rB));
5432:   PetscCheck(rB, PetscObjectComm((PetscObject)B), PETSC_ERR_ARG_WRONG, "Reuse matrix used was not generated from call to MatTranspose()");
5433:   PetscCall(PetscContainerGetPointer(rB, (void **)&rb));
5434:   PetscCheck(rb->id == ((PetscObject)A)->id, PetscObjectComm((PetscObject)B), PETSC_ERR_ARG_WRONG, "Reuse matrix used was not generated from input matrix");
5435:   PetscCheck(rb->nonzerostate == A->nonzerostate, PetscObjectComm((PetscObject)B), PETSC_ERR_ARG_WRONGSTATE, "Reuse matrix has changed nonzero structure");
5436:   PetscFunctionReturn(PETSC_SUCCESS);
5437: }

5439: /*@
5440:   MatIsTranspose - Test whether a matrix is another one's transpose,
5441:   or its own, in which case it tests symmetry.

5443:   Collective

5445:   Input Parameters:
5446: + A   - the matrix to test
5447: . B   - the matrix to test against, this can equal the first parameter
5448: - tol - tolerance, differences between entries smaller than this are counted as zero

5450:   Output Parameter:
5451: . flg - the result

5453:   Level: intermediate

5455:   Notes:
5456:   The sequential algorithm has a running time of the order of the number of nonzeros; the parallel
5457:   test involves parallel copies of the block off-diagonal parts of the matrix.

5459: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatIsSymmetric()`, `MatIsHermitian()`
5460: @*/
5461: PetscErrorCode MatIsTranspose(Mat A, Mat B, PetscReal tol, PetscBool *flg)
5462: {
5463:   PetscErrorCode (*f)(Mat, Mat, PetscReal, PetscBool *), (*g)(Mat, Mat, PetscReal, PetscBool *);

5465:   PetscFunctionBegin;
5468:   PetscAssertPointer(flg, 4);
5469:   PetscCall(PetscObjectQueryFunction((PetscObject)A, "MatIsTranspose_C", &f));
5470:   PetscCall(PetscObjectQueryFunction((PetscObject)B, "MatIsTranspose_C", &g));
5471:   *flg = PETSC_FALSE;
5472:   if (f && g) {
5473:     PetscCheck(f == g, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_NOTSAMETYPE, "Matrices do not have the same comparator for symmetry test");
5474:     PetscCall((*f)(A, B, tol, flg));
5475:   } else {
5476:     MatType mattype;

5478:     PetscCall(MatGetType(f ? B : A, &mattype));
5479:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Matrix of type %s does not support checking for transpose", mattype);
5480:   }
5481:   PetscFunctionReturn(PETSC_SUCCESS);
5482: }

5484: /*@
5485:   MatHermitianTranspose - Computes an in-place or out-of-place Hermitian transpose of a matrix in complex conjugate.

5487:   Collective

5489:   Input Parameters:
5490: + mat   - the matrix to transpose and complex conjugate
5491: - reuse - either `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, or `MAT_INPLACE_MATRIX`

5493:   Output Parameter:
5494: . B - the Hermitian transpose

5496:   Level: intermediate

5498: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatMultTranspose()`, `MatMultTransposeAdd()`, `MatIsTranspose()`, `MatReuse`
5499: @*/
5500: PetscErrorCode MatHermitianTranspose(Mat mat, MatReuse reuse, Mat *B)
5501: {
5502:   PetscFunctionBegin;
5503:   PetscCall(MatTranspose(mat, reuse, B));
5504: #if defined(PETSC_USE_COMPLEX)
5505:   PetscCall(MatConjugate(*B));
5506: #endif
5507:   PetscFunctionReturn(PETSC_SUCCESS);
5508: }

5510: /*@
5511:   MatIsHermitianTranspose - Test whether a matrix is another one's Hermitian transpose,

5513:   Collective

5515:   Input Parameters:
5516: + A   - the matrix to test
5517: . B   - the matrix to test against, this can equal the first parameter
5518: - tol - tolerance, differences between entries smaller than this are counted as zero

5520:   Output Parameter:
5521: . flg - the result

5523:   Level: intermediate

5525:   Notes:
5526:   Only available for `MATAIJ` matrices.

5528:   The sequential algorithm
5529:   has a running time of the order of the number of nonzeros; the parallel
5530:   test involves parallel copies of the block off-diagonal parts of the matrix.

5532: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatIsSymmetric()`, `MatIsHermitian()`, `MatIsTranspose()`
5533: @*/
5534: PetscErrorCode MatIsHermitianTranspose(Mat A, Mat B, PetscReal tol, PetscBool *flg)
5535: {
5536:   PetscErrorCode (*f)(Mat, Mat, PetscReal, PetscBool *), (*g)(Mat, Mat, PetscReal, PetscBool *);

5538:   PetscFunctionBegin;
5541:   PetscAssertPointer(flg, 4);
5542:   PetscCall(PetscObjectQueryFunction((PetscObject)A, "MatIsHermitianTranspose_C", &f));
5543:   PetscCall(PetscObjectQueryFunction((PetscObject)B, "MatIsHermitianTranspose_C", &g));
5544:   if (f && g) {
5545:     PetscCheck(f != g, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_NOTSAMETYPE, "Matrices do not have the same comparator for Hermitian test");
5546:     PetscCall((*f)(A, B, tol, flg));
5547:   }
5548:   PetscFunctionReturn(PETSC_SUCCESS);
5549: }

5551: /*@
5552:   MatPermute - Creates a new matrix with rows and columns permuted from the
5553:   original.

5555:   Collective

5557:   Input Parameters:
5558: + mat - the matrix to permute
5559: . row - row permutation, each processor supplies only the permutation for its rows
5560: - col - column permutation, each processor supplies only the permutation for its columns

5562:   Output Parameter:
5563: . B - the permuted matrix

5565:   Level: advanced

5567:   Note:
5568:   The index sets map from row/col of permuted matrix to row/col of original matrix.
5569:   The index sets should be on the same communicator as mat and have the same local sizes.

5571:   Developer Note:
5572:   If you want to implement `MatPermute()` for a matrix type, and your approach doesn't
5573:   exploit the fact that row and col are permutations, consider implementing the
5574:   more general `MatCreateSubMatrix()` instead.

5576: .seealso: [](ch_matrices), `Mat`, `MatGetOrdering()`, `ISAllGather()`, `MatCreateSubMatrix()`
5577: @*/
5578: PetscErrorCode MatPermute(Mat mat, IS row, IS col, Mat *B)
5579: {
5580:   PetscFunctionBegin;
5585:   PetscAssertPointer(B, 4);
5586:   PetscCheckSameComm(mat, 1, row, 2);
5587:   if (row != col) PetscCheckSameComm(row, 2, col, 3);
5588:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5589:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5590:   PetscCheck(mat->ops->permute || mat->ops->createsubmatrix, PETSC_COMM_SELF, PETSC_ERR_SUP, "MatPermute not available for Mat type %s", ((PetscObject)mat)->type_name);
5591:   MatCheckPreallocated(mat, 1);

5593:   if (mat->ops->permute) {
5594:     PetscUseTypeMethod(mat, permute, row, col, B);
5595:     PetscCall(PetscObjectStateIncrease((PetscObject)*B));
5596:   } else {
5597:     PetscCall(MatCreateSubMatrix(mat, row, col, MAT_INITIAL_MATRIX, B));
5598:   }
5599:   PetscFunctionReturn(PETSC_SUCCESS);
5600: }

5602: /*@
5603:   MatEqual - Compares two matrices.

5605:   Collective

5607:   Input Parameters:
5608: + A - the first matrix
5609: - B - the second matrix

5611:   Output Parameter:
5612: . flg - `PETSC_TRUE` if the matrices are equal; `PETSC_FALSE` otherwise.

5614:   Level: intermediate

5616:   Note:
5617:   If either of the matrix is "matrix-free", meaning the matrix entries are not stored explicitly then equality is determined by comparing the results of several matrix-vector product
5618:   using several randomly created vectors, see `MatMultEqual()`.

5620: .seealso: [](ch_matrices), `Mat`, `MatMultEqual()`
5621: @*/
5622: PetscErrorCode MatEqual(Mat A, Mat B, PetscBool *flg)
5623: {
5624:   PetscFunctionBegin;
5629:   PetscAssertPointer(flg, 3);
5630:   PetscCheckSameComm(A, 1, B, 2);
5631:   MatCheckPreallocated(A, 1);
5632:   MatCheckPreallocated(B, 2);
5633:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5634:   PetscCheck(B->assembled, PetscObjectComm((PetscObject)B), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5635:   PetscCheck(A->rmap->N == B->rmap->N && A->cmap->N == B->cmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat B: global dim %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->N, B->rmap->N, A->cmap->N,
5636:              B->cmap->N);
5637:   if (A->ops->equal && A->ops->equal == B->ops->equal) {
5638:     PetscUseTypeMethod(A, equal, B, flg);
5639:   } else {
5640:     PetscCall(MatMultEqual(A, B, 10, flg));
5641:   }
5642:   PetscFunctionReturn(PETSC_SUCCESS);
5643: }

5645: /*@
5646:   MatDiagonalScale - Scales a matrix on the left and right by diagonal
5647:   matrices that are stored as vectors.  Either of the two scaling
5648:   matrices can be `NULL`.

5650:   Collective

5652:   Input Parameters:
5653: + mat - the matrix to be scaled
5654: . l   - the left scaling vector (or `NULL`)
5655: - r   - the right scaling vector (or `NULL`)

5657:   Level: intermediate

5659:   Note:
5660:   `MatDiagonalScale()` computes $A = LAR$, where
5661:   L = a diagonal matrix (stored as a vector), R = a diagonal matrix (stored as a vector)
5662:   The L scales the rows of the matrix, the R scales the columns of the matrix.

5664: .seealso: [](ch_matrices), `Mat`, `MatScale()`, `MatShift()`, `MatDiagonalSet()`
5665: @*/
5666: PetscErrorCode MatDiagonalScale(Mat mat, Vec l, Vec r)
5667: {
5668:   PetscFunctionBegin;
5671:   if (l) {
5673:     PetscCheckSameComm(mat, 1, l, 2);
5674:   }
5675:   if (r) {
5677:     PetscCheckSameComm(mat, 1, r, 3);
5678:   }
5679:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5680:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5681:   MatCheckPreallocated(mat, 1);
5682:   if (!l && !r) PetscFunctionReturn(PETSC_SUCCESS);

5684:   PetscCall(PetscLogEventBegin(MAT_Scale, mat, 0, 0, 0));
5685:   PetscUseTypeMethod(mat, diagonalscale, l, r);
5686:   PetscCall(PetscLogEventEnd(MAT_Scale, mat, 0, 0, 0));
5687:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
5688:   if (l != r) mat->symmetric = PETSC_BOOL3_FALSE;
5689:   PetscFunctionReturn(PETSC_SUCCESS);
5690: }

5692: /*@
5693:   MatScale - Scales all elements of a matrix by a given number.

5695:   Logically Collective

5697:   Input Parameters:
5698: + mat - the matrix to be scaled
5699: - a   - the scaling value

5701:   Level: intermediate

5703: .seealso: [](ch_matrices), `Mat`, `MatDiagonalScale()`
5704: @*/
5705: PetscErrorCode MatScale(Mat mat, PetscScalar a)
5706: {
5707:   PetscFunctionBegin;
5710:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5711:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5713:   MatCheckPreallocated(mat, 1);

5715:   PetscCall(PetscLogEventBegin(MAT_Scale, mat, 0, 0, 0));
5716:   if (a != (PetscScalar)1.0) {
5717:     PetscUseTypeMethod(mat, scale, a);
5718:     PetscCall(PetscObjectStateIncrease((PetscObject)mat));
5719:   }
5720:   PetscCall(PetscLogEventEnd(MAT_Scale, mat, 0, 0, 0));
5721:   PetscFunctionReturn(PETSC_SUCCESS);
5722: }

5724: /*@
5725:   MatNorm - Calculates various norms of a matrix.

5727:   Collective

5729:   Input Parameters:
5730: + mat  - the matrix
5731: - type - the type of norm, `NORM_1`, `NORM_FROBENIUS`, `NORM_INFINITY`

5733:   Output Parameter:
5734: . nrm - the resulting norm

5736:   Level: intermediate

5738: .seealso: [](ch_matrices), `Mat`
5739: @*/
5740: PetscErrorCode MatNorm(Mat mat, NormType type, PetscReal *nrm)
5741: {
5742:   PetscFunctionBegin;
5745:   PetscAssertPointer(nrm, 3);

5747:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5748:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5749:   MatCheckPreallocated(mat, 1);

5751:   PetscUseTypeMethod(mat, norm, type, nrm);
5752:   PetscFunctionReturn(PETSC_SUCCESS);
5753: }

5755: /*
5756:      This variable is used to prevent counting of MatAssemblyBegin() that
5757:    are called from within a MatAssemblyEnd().
5758: */
5759: static PetscInt MatAssemblyEnd_InUse = 0;
5760: /*@
5761:   MatAssemblyBegin - Begins assembling the matrix.  This routine should
5762:   be called after completing all calls to `MatSetValues()`.

5764:   Collective

5766:   Input Parameters:
5767: + mat  - the matrix
5768: - type - type of assembly, either `MAT_FLUSH_ASSEMBLY` or `MAT_FINAL_ASSEMBLY`

5770:   Level: beginner

5772:   Notes:
5773:   `MatSetValues()` generally caches the values that belong to other MPI processes.  The matrix is ready to
5774:   use only after `MatAssemblyBegin()` and `MatAssemblyEnd()` have been called.

5776:   Use `MAT_FLUSH_ASSEMBLY` when switching between `ADD_VALUES` and `INSERT_VALUES`
5777:   in `MatSetValues()`; use `MAT_FINAL_ASSEMBLY` for the final assembly before
5778:   using the matrix.

5780:   ALL processes that share a matrix MUST call `MatAssemblyBegin()` and `MatAssemblyEnd()` the SAME NUMBER of times, and each time with the
5781:   same flag of `MAT_FLUSH_ASSEMBLY` or `MAT_FINAL_ASSEMBLY` for all processes. Thus you CANNOT locally change from `ADD_VALUES` to `INSERT_VALUES`, that is
5782:   a global collective operation requiring all processes that share the matrix.

5784:   Space for preallocated nonzeros that is not filled by a call to `MatSetValues()` or a related routine are compressed
5785:   out by assembly. If you intend to use that extra space on a subsequent assembly, be sure to insert explicit zeros
5786:   before `MAT_FINAL_ASSEMBLY` so the space is not compressed out.

5788: .seealso: [](ch_matrices), `Mat`, `MatAssemblyEnd()`, `MatSetValues()`, `MatAssembled()`
5789: @*/
5790: PetscErrorCode MatAssemblyBegin(Mat mat, MatAssemblyType type)
5791: {
5792:   PetscFunctionBegin;
5795:   MatCheckPreallocated(mat, 1);
5796:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix. Did you forget to call MatSetUnfactored()?");
5797:   if (mat->assembled) {
5798:     mat->was_assembled = PETSC_TRUE;
5799:     mat->assembled     = PETSC_FALSE;
5800:   }

5802:   if (!MatAssemblyEnd_InUse) {
5803:     PetscCall(PetscLogEventBegin(MAT_AssemblyBegin, mat, 0, 0, 0));
5804:     PetscTryTypeMethod(mat, assemblybegin, type);
5805:     PetscCall(PetscLogEventEnd(MAT_AssemblyBegin, mat, 0, 0, 0));
5806:   } else PetscTryTypeMethod(mat, assemblybegin, type);
5807:   PetscFunctionReturn(PETSC_SUCCESS);
5808: }

5810: /*@
5811:   MatAssembled - Indicates if a matrix has been assembled and is ready for
5812:   use; for example, in matrix-vector product.

5814:   Not Collective

5816:   Input Parameter:
5817: . mat - the matrix

5819:   Output Parameter:
5820: . assembled - `PETSC_TRUE` or `PETSC_FALSE`

5822:   Level: advanced

5824: .seealso: [](ch_matrices), `Mat`, `MatAssemblyEnd()`, `MatSetValues()`, `MatAssemblyBegin()`
5825: @*/
5826: PetscErrorCode MatAssembled(Mat mat, PetscBool *assembled)
5827: {
5828:   PetscFunctionBegin;
5830:   PetscAssertPointer(assembled, 2);
5831:   *assembled = mat->assembled;
5832:   PetscFunctionReturn(PETSC_SUCCESS);
5833: }

5835: /*@
5836:   MatAssemblyEnd - Completes assembling the matrix.  This routine should
5837:   be called after `MatAssemblyBegin()`.

5839:   Collective

5841:   Input Parameters:
5842: + mat  - the matrix
5843: - type - type of assembly, either `MAT_FLUSH_ASSEMBLY` or `MAT_FINAL_ASSEMBLY`

5845:   Options Database Keys:
5846: + -mat_view ::ascii_info             - Prints info on matrix at conclusion of `MatAssemblyEnd()`
5847: . -mat_view ::ascii_info_detail      - Prints more detailed info
5848: . -mat_view                          - Prints matrix in ASCII format
5849: . -mat_view ::ascii_matlab           - Prints matrix in MATLAB format
5850: . -mat_view draw                     - draws nonzero structure of matrix, using `MatView()` and `PetscDrawOpenX()`.
5851: . -display <name>                    - Sets display name (default is host)
5852: . -draw_pause <sec>                  - Sets number of seconds to pause after display
5853: . -mat_view socket                   - Sends matrix to socket, can be accessed from MATLAB (See [Using MATLAB with PETSc](ch_matlab))
5854: . -viewer_socket_machine <machine>   - Machine to use for socket
5855: . -viewer_socket_port <port>         - Port number to use for socket
5856: - -mat_view binary:filename[:append] - Save matrix to file in binary format

5858:   Level: beginner

5860: .seealso: [](ch_matrices), `Mat`, `MatAssemblyBegin()`, `MatSetValues()`, `PetscDrawOpenX()`, `PetscDrawCreate()`, `MatView()`, `MatAssembled()`, `PetscViewerSocketOpen()`
5861: @*/
5862: PetscErrorCode MatAssemblyEnd(Mat mat, MatAssemblyType type)
5863: {
5864:   static PetscInt inassm = 0;
5865:   PetscBool       flg    = PETSC_FALSE;

5867:   PetscFunctionBegin;

5871:   inassm++;
5872:   MatAssemblyEnd_InUse++;
5873:   if (MatAssemblyEnd_InUse == 1) { /* Do the logging only the first time through */
5874:     PetscCall(PetscLogEventBegin(MAT_AssemblyEnd, mat, 0, 0, 0));
5875:     PetscTryTypeMethod(mat, assemblyend, type);
5876:     PetscCall(PetscLogEventEnd(MAT_AssemblyEnd, mat, 0, 0, 0));
5877:   } else PetscTryTypeMethod(mat, assemblyend, type);

5879:   /* Flush assembly is not a true assembly */
5880:   if (type != MAT_FLUSH_ASSEMBLY) {
5881:     if (mat->num_ass) {
5882:       if (!mat->symmetry_eternal) {
5883:         mat->symmetric = PETSC_BOOL3_UNKNOWN;
5884:         mat->hermitian = PETSC_BOOL3_UNKNOWN;
5885:       }
5886:       if (!mat->structural_symmetry_eternal && mat->ass_nonzerostate != mat->nonzerostate) mat->structurally_symmetric = PETSC_BOOL3_UNKNOWN;
5887:       if (!mat->spd_eternal) mat->spd = PETSC_BOOL3_UNKNOWN;
5888:     }
5889:     mat->num_ass++;
5890:     mat->assembled        = PETSC_TRUE;
5891:     mat->ass_nonzerostate = mat->nonzerostate;
5892:   }

5894:   mat->insertmode = NOT_SET_VALUES;
5895:   MatAssemblyEnd_InUse--;
5896:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
5897:   if (inassm == 1 && type != MAT_FLUSH_ASSEMBLY) {
5898:     PetscCall(MatViewFromOptions(mat, NULL, "-mat_view"));

5900:     if (mat->checksymmetryonassembly) {
5901:       PetscCall(MatIsSymmetric(mat, mat->checksymmetrytol, &flg));
5902:       if (flg) {
5903:         PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "Matrix is symmetric (tolerance %g)\n", (double)mat->checksymmetrytol));
5904:       } else {
5905:         PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "Matrix is not symmetric (tolerance %g)\n", (double)mat->checksymmetrytol));
5906:       }
5907:     }
5908:     if (mat->nullsp && mat->checknullspaceonassembly) PetscCall(MatNullSpaceTest(mat->nullsp, mat, NULL));
5909:   }
5910:   inassm--;
5911:   PetscFunctionReturn(PETSC_SUCCESS);
5912: }

5914: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
5915: /*@
5916:   MatSetOption - Sets a parameter option for a matrix. Some options
5917:   may be specific to certain storage formats.  Some options
5918:   determine how values will be inserted (or added). Sorted,
5919:   row-oriented input will generally assemble the fastest. The default
5920:   is row-oriented.

5922:   Logically Collective for certain operations, such as `MAT_SPD`, not collective for `MAT_ROW_ORIENTED`, see `MatOption`

5924:   Input Parameters:
5925: + mat - the matrix
5926: . op  - the option, one of those listed below (and possibly others),
5927: - flg - turn the option on (`PETSC_TRUE`) or off (`PETSC_FALSE`)

5929:   Options Describing Matrix Structure:
5930: + `MAT_SPD`                         - symmetric positive definite
5931: . `MAT_SYMMETRIC`                   - symmetric in terms of both structure and value
5932: . `MAT_HERMITIAN`                   - transpose is the complex conjugation
5933: . `MAT_STRUCTURALLY_SYMMETRIC`      - symmetric nonzero structure
5934: . `MAT_SYMMETRY_ETERNAL`            - indicates the symmetry (or Hermitian structure) or its absence will persist through any changes to the matrix
5935: . `MAT_STRUCTURAL_SYMMETRY_ETERNAL` - indicates the structural symmetry or its absence will persist through any changes to the matrix
5936: . `MAT_SPD_ETERNAL`                 - indicates the value of `MAT_SPD` (true or false) will persist through any changes to the matrix

5938:    These are not really options of the matrix, they are knowledge about the structure of the matrix that users may provide so that they
5939:    do not need to be computed (usually at a high cost)

5941:    Options For Use with `MatSetValues()`:
5942:    Insert a logically dense subblock, which can be
5943: . `MAT_ROW_ORIENTED`                - row-oriented (default)

5945:    These options reflect the data you pass in with `MatSetValues()`; it has
5946:    nothing to do with how the data is stored internally in the matrix
5947:    data structure.

5949:    When (re)assembling a matrix, we can restrict the input for
5950:    efficiency/debugging purposes.  These options include
5951: . `MAT_NEW_NONZERO_LOCATIONS`       - additional insertions will be allowed if they generate a new nonzero (slow)
5952: . `MAT_FORCE_DIAGONAL_ENTRIES`      - forces diagonal entries to be allocated
5953: . `MAT_IGNORE_OFF_PROC_ENTRIES`     - drops off-processor entries
5954: . `MAT_NEW_NONZERO_LOCATION_ERR`    - generates an error for new matrix entry
5955: . `MAT_USE_HASH_TABLE`              - uses a hash table to speed up matrix assembly
5956: . `MAT_NO_OFF_PROC_ENTRIES`         - you know each process will only set values for its own rows, will generate an error if
5957:         any process sets values for another process. This avoids all reductions in the MatAssembly routines and thus improves
5958:         performance for very large process counts.
5959: - `MAT_SUBSET_OFF_PROC_ENTRIES`     - you know that the first assembly after setting this flag will set a superset
5960:         of the off-process entries required for all subsequent assemblies. This avoids a rendezvous step in the MatAssembly
5961:         functions, instead sending only neighbor messages.

5963:   Level: intermediate

5965:   Notes:
5966:   Except for `MAT_UNUSED_NONZERO_LOCATION_ERR` and  `MAT_ROW_ORIENTED` all processes that share the matrix must pass the same value in flg!

5968:   Some options are relevant only for particular matrix types and
5969:   are thus ignored by others.  Other options are not supported by
5970:   certain matrix types and will generate an error message if set.

5972:   If using Fortran to compute a matrix, one may need to
5973:   use the column-oriented option (or convert to the row-oriented
5974:   format).

5976:   `MAT_NEW_NONZERO_LOCATIONS` set to `PETSC_FALSE` indicates that any add or insertion
5977:   that would generate a new entry in the nonzero structure is instead
5978:   ignored.  Thus, if memory has not already been allocated for this particular
5979:   data, then the insertion is ignored. For dense matrices, in which
5980:   the entire array is allocated, no entries are ever ignored.
5981:   Set after the first `MatAssemblyEnd()`. If this option is set, then the `MatAssemblyBegin()`/`MatAssemblyEnd()` processes has one less global reduction

5983:   `MAT_NEW_NONZERO_LOCATION_ERR` set to PETSC_TRUE indicates that any add or insertion
5984:   that would generate a new entry in the nonzero structure instead produces
5985:   an error. (Currently supported for `MATAIJ` and `MATBAIJ` formats only.) If this option is set, then the `MatAssemblyBegin()`/`MatAssemblyEnd()` processes has one less global reduction

5987:   `MAT_NEW_NONZERO_ALLOCATION_ERR` set to `PETSC_TRUE` indicates that any add or insertion
5988:   that would generate a new entry that has not been preallocated will
5989:   instead produce an error. (Currently supported for `MATAIJ` and `MATBAIJ` formats
5990:   only.) This is a useful flag when debugging matrix memory preallocation.
5991:   If this option is set, then the `MatAssemblyBegin()`/`MatAssemblyEnd()` processes has one less global reduction

5993:   `MAT_IGNORE_OFF_PROC_ENTRIES` set to `PETSC_TRUE` indicates entries destined for
5994:   other processors should be dropped, rather than stashed.
5995:   This is useful if you know that the "owning" processor is also
5996:   always generating the correct matrix entries, so that PETSc need
5997:   not transfer duplicate entries generated on another processor.

5999:   `MAT_USE_HASH_TABLE` indicates that a hash table be used to improve the
6000:   searches during matrix assembly. When this flag is set, the hash table
6001:   is created during the first matrix assembly. This hash table is
6002:   used the next time through, during `MatSetValues()`/`MatSetValuesBlocked()`
6003:   to improve the searching of indices. `MAT_NEW_NONZERO_LOCATIONS` flag
6004:   should be used with `MAT_USE_HASH_TABLE` flag. This option is currently
6005:   supported by `MATMPIBAIJ` format only.

6007:   `MAT_KEEP_NONZERO_PATTERN` indicates when `MatZeroRows()` is called the zeroed entries
6008:   are kept in the nonzero structure. This flag is not used for `MatZeroRowsColumns()`

6010:   `MAT_IGNORE_ZERO_ENTRIES` - for `MATAIJ` and `MATIS` matrices this will stop zero values from creating
6011:   a zero location in the matrix

6013:   `MAT_USE_INODES` - indicates using inode version of the code - works with `MATAIJ` matrix types

6015:   `MAT_NO_OFF_PROC_ZERO_ROWS` - you know each process will only zero its own rows. This avoids all reductions in the
6016:   zero row routines and thus improves performance for very large process counts.

6018:   `MAT_IGNORE_LOWER_TRIANGULAR` - For `MATSBAIJ` matrices will ignore any insertions you make in the lower triangular
6019:   part of the matrix (since they should match the upper triangular part).

6021:   `MAT_SORTED_FULL` - each process provides exactly its local rows; all column indices for a given row are passed in a
6022:   single call to `MatSetValues()`, preallocation is perfect, row-oriented, `INSERT_VALUES` is used. Common
6023:   with finite difference schemes with non-periodic boundary conditions.

6025:   Developer Note:
6026:   `MAT_SYMMETRY_ETERNAL`, `MAT_STRUCTURAL_SYMMETRY_ETERNAL`, and `MAT_SPD_ETERNAL` are used by `MatAssemblyEnd()` and in other
6027:   places where otherwise the value of `MAT_SYMMETRIC`, `MAT_STRUCTURALLY_SYMMETRIC` or `MAT_SPD` would need to be changed back
6028:   to `PETSC_BOOL3_UNKNOWN` because the matrix values had changed so the code cannot be certain that the related property had
6029:   not changed.

6031: .seealso: [](ch_matrices), `MatOption`, `Mat`, `MatGetOption()`
6032: @*/
6033: PetscErrorCode MatSetOption(Mat mat, MatOption op, PetscBool flg)
6034: {
6035:   PetscFunctionBegin;
6037:   if (op > 0) {
6040:   }

6042:   PetscCheck(((int)op) > MAT_OPTION_MIN && ((int)op) < MAT_OPTION_MAX, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Options %d is out of range", (int)op);

6044:   switch (op) {
6045:   case MAT_FORCE_DIAGONAL_ENTRIES:
6046:     mat->force_diagonals = flg;
6047:     PetscFunctionReturn(PETSC_SUCCESS);
6048:   case MAT_NO_OFF_PROC_ENTRIES:
6049:     mat->nooffprocentries = flg;
6050:     PetscFunctionReturn(PETSC_SUCCESS);
6051:   case MAT_SUBSET_OFF_PROC_ENTRIES:
6052:     mat->assembly_subset = flg;
6053:     if (!mat->assembly_subset) { /* See the same logic in VecAssembly wrt VEC_SUBSET_OFF_PROC_ENTRIES */
6054: #if !defined(PETSC_HAVE_MPIUNI)
6055:       PetscCall(MatStashScatterDestroy_BTS(&mat->stash));
6056: #endif
6057:       mat->stash.first_assembly_done = PETSC_FALSE;
6058:     }
6059:     PetscFunctionReturn(PETSC_SUCCESS);
6060:   case MAT_NO_OFF_PROC_ZERO_ROWS:
6061:     mat->nooffproczerorows = flg;
6062:     PetscFunctionReturn(PETSC_SUCCESS);
6063:   case MAT_SPD:
6064:     if (flg) {
6065:       mat->spd                    = PETSC_BOOL3_TRUE;
6066:       mat->symmetric              = PETSC_BOOL3_TRUE;
6067:       mat->structurally_symmetric = PETSC_BOOL3_TRUE;
6068:     } else {
6069:       mat->spd = PETSC_BOOL3_FALSE;
6070:     }
6071:     break;
6072:   case MAT_SYMMETRIC:
6073:     mat->symmetric = flg ? PETSC_BOOL3_TRUE : PETSC_BOOL3_FALSE;
6074:     if (flg) mat->structurally_symmetric = PETSC_BOOL3_TRUE;
6075: #if !defined(PETSC_USE_COMPLEX)
6076:     mat->hermitian = flg ? PETSC_BOOL3_TRUE : PETSC_BOOL3_FALSE;
6077: #endif
6078:     break;
6079:   case MAT_HERMITIAN:
6080:     mat->hermitian = flg ? PETSC_BOOL3_TRUE : PETSC_BOOL3_FALSE;
6081:     if (flg) mat->structurally_symmetric = PETSC_BOOL3_TRUE;
6082: #if !defined(PETSC_USE_COMPLEX)
6083:     mat->symmetric = flg ? PETSC_BOOL3_TRUE : PETSC_BOOL3_FALSE;
6084: #endif
6085:     break;
6086:   case MAT_STRUCTURALLY_SYMMETRIC:
6087:     mat->structurally_symmetric = flg ? PETSC_BOOL3_TRUE : PETSC_BOOL3_FALSE;
6088:     break;
6089:   case MAT_SYMMETRY_ETERNAL:
6090:     PetscCheck(mat->symmetric != PETSC_BOOL3_UNKNOWN, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot set MAT_SYMMETRY_ETERNAL without first setting MAT_SYMMETRIC to true or false");
6091:     mat->symmetry_eternal = flg;
6092:     if (flg) mat->structural_symmetry_eternal = PETSC_TRUE;
6093:     break;
6094:   case MAT_STRUCTURAL_SYMMETRY_ETERNAL:
6095:     PetscCheck(mat->structurally_symmetric != PETSC_BOOL3_UNKNOWN, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot set MAT_STRUCTURAL_SYMMETRY_ETERNAL without first setting MAT_STRUCTURALLY_SYMMETRIC to true or false");
6096:     mat->structural_symmetry_eternal = flg;
6097:     break;
6098:   case MAT_SPD_ETERNAL:
6099:     PetscCheck(mat->spd != PETSC_BOOL3_UNKNOWN, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot set MAT_SPD_ETERNAL without first setting MAT_SPD to true or false");
6100:     mat->spd_eternal = flg;
6101:     if (flg) {
6102:       mat->structural_symmetry_eternal = PETSC_TRUE;
6103:       mat->symmetry_eternal            = PETSC_TRUE;
6104:     }
6105:     break;
6106:   case MAT_STRUCTURE_ONLY:
6107:     mat->structure_only = flg;
6108:     break;
6109:   case MAT_SORTED_FULL:
6110:     mat->sortedfull = flg;
6111:     break;
6112:   default:
6113:     break;
6114:   }
6115:   PetscTryTypeMethod(mat, setoption, op, flg);
6116:   PetscFunctionReturn(PETSC_SUCCESS);
6117: }

6119: /*@
6120:   MatGetOption - Gets a parameter option that has been set for a matrix.

6122:   Logically Collective

6124:   Input Parameters:
6125: + mat - the matrix
6126: - op  - the option, this only responds to certain options, check the code for which ones

6128:   Output Parameter:
6129: . flg - turn the option on (`PETSC_TRUE`) or off (`PETSC_FALSE`)

6131:   Level: intermediate

6133:   Notes:
6134:   Can only be called after `MatSetSizes()` and `MatSetType()` have been set.

6136:   Certain option values may be unknown, for those use the routines `MatIsSymmetric()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, or
6137:   `MatIsSymmetricKnown()`, `MatIsHermitianKnown()`, `MatIsStructurallySymmetricKnown()`

6139: .seealso: [](ch_matrices), `Mat`, `MatOption`, `MatSetOption()`, `MatIsSymmetric()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`,
6140:     `MatIsSymmetricKnown()`, `MatIsHermitianKnown()`, `MatIsStructurallySymmetricKnown()`
6141: @*/
6142: PetscErrorCode MatGetOption(Mat mat, MatOption op, PetscBool *flg)
6143: {
6144:   PetscFunctionBegin;

6148:   PetscCheck(((int)op) > MAT_OPTION_MIN && ((int)op) < MAT_OPTION_MAX, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Options %d is out of range", (int)op);
6149:   PetscCheck(((PetscObject)mat)->type_name, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_TYPENOTSET, "Cannot get options until type and size have been set, see MatSetType() and MatSetSizes()");

6151:   switch (op) {
6152:   case MAT_NO_OFF_PROC_ENTRIES:
6153:     *flg = mat->nooffprocentries;
6154:     break;
6155:   case MAT_NO_OFF_PROC_ZERO_ROWS:
6156:     *flg = mat->nooffproczerorows;
6157:     break;
6158:   case MAT_SYMMETRIC:
6159:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Use MatIsSymmetric() or MatIsSymmetricKnown()");
6160:     break;
6161:   case MAT_HERMITIAN:
6162:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Use MatIsHermitian() or MatIsHermitianKnown()");
6163:     break;
6164:   case MAT_STRUCTURALLY_SYMMETRIC:
6165:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Use MatIsStructurallySymmetric() or MatIsStructurallySymmetricKnown()");
6166:     break;
6167:   case MAT_SPD:
6168:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Use MatIsSPDKnown()");
6169:     break;
6170:   case MAT_SYMMETRY_ETERNAL:
6171:     *flg = mat->symmetry_eternal;
6172:     break;
6173:   case MAT_STRUCTURAL_SYMMETRY_ETERNAL:
6174:     *flg = mat->symmetry_eternal;
6175:     break;
6176:   default:
6177:     break;
6178:   }
6179:   PetscFunctionReturn(PETSC_SUCCESS);
6180: }

6182: /*@
6183:   MatZeroEntries - Zeros all entries of a matrix.  For sparse matrices
6184:   this routine retains the old nonzero structure.

6186:   Logically Collective

6188:   Input Parameter:
6189: . mat - the matrix

6191:   Level: intermediate

6193:   Note:
6194:   If the matrix was not preallocated then a default, likely poor preallocation will be set in the matrix, so this should be called after the preallocation phase.
6195:   See the Performance chapter of the users manual for information on preallocating matrices.

6197: .seealso: [](ch_matrices), `Mat`, `MatZeroRows()`, `MatZeroRowsColumns()`
6198: @*/
6199: PetscErrorCode MatZeroEntries(Mat mat)
6200: {
6201:   PetscFunctionBegin;
6204:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6205:   PetscCheck(mat->insertmode == NOT_SET_VALUES, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for matrices where you have set values but not yet assembled");
6206:   MatCheckPreallocated(mat, 1);

6208:   PetscCall(PetscLogEventBegin(MAT_ZeroEntries, mat, 0, 0, 0));
6209:   PetscUseTypeMethod(mat, zeroentries);
6210:   PetscCall(PetscLogEventEnd(MAT_ZeroEntries, mat, 0, 0, 0));
6211:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6212:   PetscFunctionReturn(PETSC_SUCCESS);
6213: }

6215: /*@
6216:   MatZeroRowsColumns - Zeros all entries (except possibly the main diagonal)
6217:   of a set of rows and columns of a matrix.

6219:   Collective

6221:   Input Parameters:
6222: + mat     - the matrix
6223: . numRows - the number of rows/columns to zero
6224: . rows    - the global row indices
6225: . diag    - value put in the diagonal of the eliminated rows
6226: . x       - optional vector of the solution for zeroed rows (other entries in vector are not used), these must be set before this call
6227: - b       - optional vector of the right-hand side, that will be adjusted by provided solution entries

6229:   Level: intermediate

6231:   Notes:
6232:   This routine, along with `MatZeroRows()`, is typically used to eliminate known Dirichlet boundary conditions from a linear system.

6234:   For each zeroed row, the value of the corresponding `b` is set to diag times the value of the corresponding `x`.
6235:   The other entries of `b` will be adjusted by the known values of `x` times the corresponding matrix entries in the columns that are being eliminated

6237:   If the resulting linear system is to be solved with `KSP` then one can (but does not have to) call `KSPSetInitialGuessNonzero()` to allow the
6238:   Krylov method to take advantage of the known solution on the zeroed rows.

6240:   For the parallel case, all processes that share the matrix (i.e.,
6241:   those in the communicator used for matrix creation) MUST call this
6242:   routine, regardless of whether any rows being zeroed are owned by
6243:   them.

6245:   Unlike `MatZeroRows()`, this ignores the `MAT_KEEP_NONZERO_PATTERN` option value set with `MatSetOption()`, it merely zeros those entries in the matrix, but never
6246:   removes them from the nonzero pattern. The nonzero pattern of the matrix can still change if a nonzero needs to be inserted on a diagonal entry that was previously
6247:   missing.

6249:   Each processor can indicate any rows in the entire matrix to be zeroed (i.e. each process does NOT have to
6250:   list only rows local to itself).

6252:   The option `MAT_NO_OFF_PROC_ZERO_ROWS` does not apply to this routine.

6254: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRows()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6255:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
6256: @*/
6257: PetscErrorCode MatZeroRowsColumns(Mat mat, PetscInt numRows, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
6258: {
6259:   PetscFunctionBegin;
6262:   if (numRows) PetscAssertPointer(rows, 3);
6263:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6264:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6265:   MatCheckPreallocated(mat, 1);

6267:   PetscUseTypeMethod(mat, zerorowscolumns, numRows, rows, diag, x, b);
6268:   PetscCall(MatViewFromOptions(mat, NULL, "-mat_view"));
6269:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6270:   PetscFunctionReturn(PETSC_SUCCESS);
6271: }

6273: /*@
6274:   MatZeroRowsColumnsIS - Zeros all entries (except possibly the main diagonal)
6275:   of a set of rows and columns of a matrix.

6277:   Collective

6279:   Input Parameters:
6280: + mat  - the matrix
6281: . is   - the rows to zero
6282: . diag - value put in all diagonals of eliminated rows (0.0 will even eliminate diagonal entry)
6283: . x    - optional vector of solutions for zeroed rows (other entries in vector are not used)
6284: - b    - optional vector of right-hand side, that will be adjusted by provided solution

6286:   Level: intermediate

6288:   Note:
6289:   See `MatZeroRowsColumns()` for details on how this routine operates.

6291: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6292:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRows()`, `MatZeroRowsColumnsStencil()`
6293: @*/
6294: PetscErrorCode MatZeroRowsColumnsIS(Mat mat, IS is, PetscScalar diag, Vec x, Vec b)
6295: {
6296:   PetscInt        numRows;
6297:   const PetscInt *rows;

6299:   PetscFunctionBegin;
6304:   PetscCall(ISGetLocalSize(is, &numRows));
6305:   PetscCall(ISGetIndices(is, &rows));
6306:   PetscCall(MatZeroRowsColumns(mat, numRows, rows, diag, x, b));
6307:   PetscCall(ISRestoreIndices(is, &rows));
6308:   PetscFunctionReturn(PETSC_SUCCESS);
6309: }

6311: /*@
6312:   MatZeroRows - Zeros all entries (except possibly the main diagonal)
6313:   of a set of rows of a matrix.

6315:   Collective

6317:   Input Parameters:
6318: + mat     - the matrix
6319: . numRows - the number of rows to zero
6320: . rows    - the global row indices
6321: . diag    - value put in the diagonal of the zeroed rows
6322: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used), these must be set before this call
6323: - b       - optional vector of right-hand side, that will be adjusted by provided solution entries

6325:   Level: intermediate

6327:   Notes:
6328:   This routine, along with `MatZeroRowsColumns()`, is typically used to eliminate known Dirichlet boundary conditions from a linear system.

6330:   For each zeroed row, the value of the corresponding `b` is set to `diag` times the value of the corresponding `x`.

6332:   If the resulting linear system is to be solved with `KSP` then one can (but does not have to) call `KSPSetInitialGuessNonzero()` to allow the
6333:   Krylov method to take advantage of the known solution on the zeroed rows.

6335:   May be followed by using a `PC` of type `PCREDISTRIBUTE` to solve the reduced problem (`PCDISTRIBUTE` completely eliminates the zeroed rows and their corresponding columns)
6336:   from the matrix.

6338:   Unlike `MatZeroRowsColumns()` for the `MATAIJ` and `MATBAIJ` matrix formats this removes the old nonzero structure, from the eliminated rows of the matrix
6339:   but does not release memory.  Because of this removal matrix-vector products with the adjusted matrix will be a bit faster. For the dense
6340:   formats this does not alter the nonzero structure.

6342:   If the option `MatSetOption`(mat,`MAT_KEEP_NONZERO_PATTERN`,`PETSC_TRUE`) the nonzero structure
6343:   of the matrix is not changed the values are
6344:   merely zeroed.

6346:   The user can set a value in the diagonal entry (or for the `MATAIJ` format
6347:   formats can optionally remove the main diagonal entry from the
6348:   nonzero structure as well, by passing 0.0 as the final argument).

6350:   For the parallel case, all processes that share the matrix (i.e.,
6351:   those in the communicator used for matrix creation) MUST call this
6352:   routine, regardless of whether any rows being zeroed are owned by
6353:   them.

6355:   Each processor can indicate any rows in the entire matrix to be zeroed (i.e. each process does NOT have to
6356:   list only rows local to itself).

6358:   You can call `MatSetOption`(mat,`MAT_NO_OFF_PROC_ZERO_ROWS`,`PETSC_TRUE`) if each process indicates only rows it
6359:   owns that are to be zeroed. This saves a global synchronization in the implementation.

6361: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6362:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`, `PCREDISTRIBUTE`, `MAT_KEEP_NONZERO_PATTERN`
6363: @*/
6364: PetscErrorCode MatZeroRows(Mat mat, PetscInt numRows, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
6365: {
6366:   PetscFunctionBegin;
6369:   if (numRows) PetscAssertPointer(rows, 3);
6370:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6371:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6372:   MatCheckPreallocated(mat, 1);

6374:   PetscUseTypeMethod(mat, zerorows, numRows, rows, diag, x, b);
6375:   PetscCall(MatViewFromOptions(mat, NULL, "-mat_view"));
6376:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6377:   PetscFunctionReturn(PETSC_SUCCESS);
6378: }

6380: /*@
6381:   MatZeroRowsIS - Zeros all entries (except possibly the main diagonal)
6382:   of a set of rows of a matrix indicated by an `IS`

6384:   Collective

6386:   Input Parameters:
6387: + mat  - the matrix
6388: . is   - index set, `IS`, of rows to remove (if `NULL` then no row is removed)
6389: . diag - value put in all diagonals of eliminated rows
6390: . x    - optional vector of solutions for zeroed rows (other entries in vector are not used)
6391: - b    - optional vector of right-hand side, that will be adjusted by provided solution

6393:   Level: intermediate

6395:   Note:
6396:   See `MatZeroRows()` for details on how this routine operates.

6398: .seealso: [](ch_matrices), `Mat`, `MatZeroRows()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6399:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`, `IS`
6400: @*/
6401: PetscErrorCode MatZeroRowsIS(Mat mat, IS is, PetscScalar diag, Vec x, Vec b)
6402: {
6403:   PetscInt        numRows = 0;
6404:   const PetscInt *rows    = NULL;

6406:   PetscFunctionBegin;
6409:   if (is) {
6411:     PetscCall(ISGetLocalSize(is, &numRows));
6412:     PetscCall(ISGetIndices(is, &rows));
6413:   }
6414:   PetscCall(MatZeroRows(mat, numRows, rows, diag, x, b));
6415:   if (is) PetscCall(ISRestoreIndices(is, &rows));
6416:   PetscFunctionReturn(PETSC_SUCCESS);
6417: }

6419: /*@
6420:   MatZeroRowsStencil - Zeros all entries (except possibly the main diagonal)
6421:   of a set of rows of a matrix indicated by a `MatStencil`. These rows must be local to the process.

6423:   Collective

6425:   Input Parameters:
6426: + mat     - the matrix
6427: . numRows - the number of rows to remove
6428: . rows    - the grid coordinates (and component number when dof > 1) for matrix rows indicated by an array of `MatStencil`
6429: . diag    - value put in all diagonals of eliminated rows (0.0 will even eliminate diagonal entry)
6430: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used)
6431: - b       - optional vector of right-hand side, that will be adjusted by provided solution

6433:   Level: intermediate

6435:   Notes:
6436:   See `MatZeroRows()` for details on how this routine operates.

6438:   The grid coordinates are across the entire grid, not just the local portion

6440:   For periodic boundary conditions use negative indices for values to the left (below 0; that are to be
6441:   obtained by wrapping values from right edge). For values to the right of the last entry using that index plus one
6442:   etc to obtain values that obtained by wrapping the values from the left edge. This does not work for anything but the
6443:   `DM_BOUNDARY_PERIODIC` boundary type.

6445:   For indices that don't mean anything for your case (like the k index when working in 2d) or the c index when you have
6446:   a single value per point) you can skip filling those indices.

6448:   Fortran Note:
6449:   `idxm` and `idxn` should be declared as
6450: $     MatStencil idxm(4, m)
6451:   and the values inserted using
6452: .vb
6453:     idxm(MatStencil_i, 1) = i
6454:     idxm(MatStencil_j, 1) = j
6455:     idxm(MatStencil_k, 1) = k
6456:     idxm(MatStencil_c, 1) = c
6457:    etc
6458: .ve

6460: .seealso: [](ch_matrices), `Mat`, `MatStencil`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRows()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6461:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
6462: @*/
6463: PetscErrorCode MatZeroRowsStencil(Mat mat, PetscInt numRows, const MatStencil rows[], PetscScalar diag, Vec x, Vec b)
6464: {
6465:   PetscInt  dim    = mat->stencil.dim;
6466:   PetscInt  sdim   = dim - (1 - (PetscInt)mat->stencil.noc);
6467:   PetscInt *dims   = mat->stencil.dims + 1;
6468:   PetscInt *starts = mat->stencil.starts;
6469:   PetscInt *dxm    = (PetscInt *)rows;
6470:   PetscInt *jdxm, i, j, tmp, numNewRows = 0;

6472:   PetscFunctionBegin;
6475:   if (numRows) PetscAssertPointer(rows, 3);

6477:   PetscCall(PetscMalloc1(numRows, &jdxm));
6478:   for (i = 0; i < numRows; ++i) {
6479:     /* Skip unused dimensions (they are ordered k, j, i, c) */
6480:     for (j = 0; j < 3 - sdim; ++j) dxm++;
6481:     /* Local index in X dir */
6482:     tmp = *dxm++ - starts[0];
6483:     /* Loop over remaining dimensions */
6484:     for (j = 0; j < dim - 1; ++j) {
6485:       /* If nonlocal, set index to be negative */
6486:       if ((*dxm++ - starts[j + 1]) < 0 || tmp < 0) tmp = PETSC_INT_MIN;
6487:       /* Update local index */
6488:       else tmp = tmp * dims[j] + *(dxm - 1) - starts[j + 1];
6489:     }
6490:     /* Skip component slot if necessary */
6491:     if (mat->stencil.noc) dxm++;
6492:     /* Local row number */
6493:     if (tmp >= 0) jdxm[numNewRows++] = tmp;
6494:   }
6495:   PetscCall(MatZeroRowsLocal(mat, numNewRows, jdxm, diag, x, b));
6496:   PetscCall(PetscFree(jdxm));
6497:   PetscFunctionReturn(PETSC_SUCCESS);
6498: }

6500: /*@
6501:   MatZeroRowsColumnsStencil - Zeros all row and column entries (except possibly the main diagonal)
6502:   of a set of rows and columns of a matrix.

6504:   Collective

6506:   Input Parameters:
6507: + mat     - the matrix
6508: . numRows - the number of rows/columns to remove
6509: . rows    - the grid coordinates (and component number when dof > 1) for matrix rows
6510: . diag    - value put in all diagonals of eliminated rows (0.0 will even eliminate diagonal entry)
6511: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used)
6512: - b       - optional vector of right-hand side, that will be adjusted by provided solution

6514:   Level: intermediate

6516:   Notes:
6517:   See `MatZeroRowsColumns()` for details on how this routine operates.

6519:   The grid coordinates are across the entire grid, not just the local portion

6521:   For periodic boundary conditions use negative indices for values to the left (below 0; that are to be
6522:   obtained by wrapping values from right edge). For values to the right of the last entry using that index plus one
6523:   etc to obtain values that obtained by wrapping the values from the left edge. This does not work for anything but the
6524:   `DM_BOUNDARY_PERIODIC` boundary type.

6526:   For indices that don't mean anything for your case (like the k index when working in 2d) or the c index when you have
6527:   a single value per point) you can skip filling those indices.

6529:   Fortran Note:
6530:   `idxm` and `idxn` should be declared as
6531: $     MatStencil idxm(4, m)
6532:   and the values inserted using
6533: .vb
6534:     idxm(MatStencil_i, 1) = i
6535:     idxm(MatStencil_j, 1) = j
6536:     idxm(MatStencil_k, 1) = k
6537:     idxm(MatStencil_c, 1) = c
6538:     etc
6539: .ve

6541: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6542:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRows()`
6543: @*/
6544: PetscErrorCode MatZeroRowsColumnsStencil(Mat mat, PetscInt numRows, const MatStencil rows[], PetscScalar diag, Vec x, Vec b)
6545: {
6546:   PetscInt  dim    = mat->stencil.dim;
6547:   PetscInt  sdim   = dim - (1 - (PetscInt)mat->stencil.noc);
6548:   PetscInt *dims   = mat->stencil.dims + 1;
6549:   PetscInt *starts = mat->stencil.starts;
6550:   PetscInt *dxm    = (PetscInt *)rows;
6551:   PetscInt *jdxm, i, j, tmp, numNewRows = 0;

6553:   PetscFunctionBegin;
6556:   if (numRows) PetscAssertPointer(rows, 3);

6558:   PetscCall(PetscMalloc1(numRows, &jdxm));
6559:   for (i = 0; i < numRows; ++i) {
6560:     /* Skip unused dimensions (they are ordered k, j, i, c) */
6561:     for (j = 0; j < 3 - sdim; ++j) dxm++;
6562:     /* Local index in X dir */
6563:     tmp = *dxm++ - starts[0];
6564:     /* Loop over remaining dimensions */
6565:     for (j = 0; j < dim - 1; ++j) {
6566:       /* If nonlocal, set index to be negative */
6567:       if ((*dxm++ - starts[j + 1]) < 0 || tmp < 0) tmp = PETSC_INT_MIN;
6568:       /* Update local index */
6569:       else tmp = tmp * dims[j] + *(dxm - 1) - starts[j + 1];
6570:     }
6571:     /* Skip component slot if necessary */
6572:     if (mat->stencil.noc) dxm++;
6573:     /* Local row number */
6574:     if (tmp >= 0) jdxm[numNewRows++] = tmp;
6575:   }
6576:   PetscCall(MatZeroRowsColumnsLocal(mat, numNewRows, jdxm, diag, x, b));
6577:   PetscCall(PetscFree(jdxm));
6578:   PetscFunctionReturn(PETSC_SUCCESS);
6579: }

6581: /*@
6582:   MatZeroRowsLocal - Zeros all entries (except possibly the main diagonal)
6583:   of a set of rows of a matrix; using local numbering of rows.

6585:   Collective

6587:   Input Parameters:
6588: + mat     - the matrix
6589: . numRows - the number of rows to remove
6590: . rows    - the local row indices
6591: . diag    - value put in all diagonals of eliminated rows
6592: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used)
6593: - b       - optional vector of right-hand side, that will be adjusted by provided solution

6595:   Level: intermediate

6597:   Notes:
6598:   Before calling `MatZeroRowsLocal()`, the user must first set the
6599:   local-to-global mapping by calling MatSetLocalToGlobalMapping(), this is often already set for matrices obtained with `DMCreateMatrix()`.

6601:   See `MatZeroRows()` for details on how this routine operates.

6603: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRows()`, `MatSetOption()`,
6604:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
6605: @*/
6606: PetscErrorCode MatZeroRowsLocal(Mat mat, PetscInt numRows, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
6607: {
6608:   PetscFunctionBegin;
6611:   if (numRows) PetscAssertPointer(rows, 3);
6612:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6613:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6614:   MatCheckPreallocated(mat, 1);

6616:   if (mat->ops->zerorowslocal) {
6617:     PetscUseTypeMethod(mat, zerorowslocal, numRows, rows, diag, x, b);
6618:   } else {
6619:     IS              is, newis;
6620:     const PetscInt *newRows;

6622:     PetscCheck(mat->rmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Need to provide local to global mapping to matrix first");
6623:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, numRows, rows, PETSC_COPY_VALUES, &is));
6624:     PetscCall(ISLocalToGlobalMappingApplyIS(mat->rmap->mapping, is, &newis));
6625:     PetscCall(ISGetIndices(newis, &newRows));
6626:     PetscUseTypeMethod(mat, zerorows, numRows, newRows, diag, x, b);
6627:     PetscCall(ISRestoreIndices(newis, &newRows));
6628:     PetscCall(ISDestroy(&newis));
6629:     PetscCall(ISDestroy(&is));
6630:   }
6631:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6632:   PetscFunctionReturn(PETSC_SUCCESS);
6633: }

6635: /*@
6636:   MatZeroRowsLocalIS - Zeros all entries (except possibly the main diagonal)
6637:   of a set of rows of a matrix; using local numbering of rows.

6639:   Collective

6641:   Input Parameters:
6642: + mat  - the matrix
6643: . is   - index set of rows to remove
6644: . diag - value put in all diagonals of eliminated rows
6645: . x    - optional vector of solutions for zeroed rows (other entries in vector are not used)
6646: - b    - optional vector of right-hand side, that will be adjusted by provided solution

6648:   Level: intermediate

6650:   Notes:
6651:   Before calling `MatZeroRowsLocalIS()`, the user must first set the
6652:   local-to-global mapping by calling `MatSetLocalToGlobalMapping()`, this is often already set for matrices obtained with `DMCreateMatrix()`.

6654:   See `MatZeroRows()` for details on how this routine operates.

6656: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRows()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6657:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
6658: @*/
6659: PetscErrorCode MatZeroRowsLocalIS(Mat mat, IS is, PetscScalar diag, Vec x, Vec b)
6660: {
6661:   PetscInt        numRows;
6662:   const PetscInt *rows;

6664:   PetscFunctionBegin;
6668:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6669:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6670:   MatCheckPreallocated(mat, 1);

6672:   PetscCall(ISGetLocalSize(is, &numRows));
6673:   PetscCall(ISGetIndices(is, &rows));
6674:   PetscCall(MatZeroRowsLocal(mat, numRows, rows, diag, x, b));
6675:   PetscCall(ISRestoreIndices(is, &rows));
6676:   PetscFunctionReturn(PETSC_SUCCESS);
6677: }

6679: /*@
6680:   MatZeroRowsColumnsLocal - Zeros all entries (except possibly the main diagonal)
6681:   of a set of rows and columns of a matrix; using local numbering of rows.

6683:   Collective

6685:   Input Parameters:
6686: + mat     - the matrix
6687: . numRows - the number of rows to remove
6688: . rows    - the global row indices
6689: . diag    - value put in all diagonals of eliminated rows
6690: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used)
6691: - b       - optional vector of right-hand side, that will be adjusted by provided solution

6693:   Level: intermediate

6695:   Notes:
6696:   Before calling `MatZeroRowsColumnsLocal()`, the user must first set the
6697:   local-to-global mapping by calling `MatSetLocalToGlobalMapping()`, this is often already set for matrices obtained with `DMCreateMatrix()`.

6699:   See `MatZeroRowsColumns()` for details on how this routine operates.

6701: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6702:           `MatZeroRows()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
6703: @*/
6704: PetscErrorCode MatZeroRowsColumnsLocal(Mat mat, PetscInt numRows, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
6705: {
6706:   IS              is, newis;
6707:   const PetscInt *newRows;

6709:   PetscFunctionBegin;
6712:   if (numRows) PetscAssertPointer(rows, 3);
6713:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6714:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6715:   MatCheckPreallocated(mat, 1);

6717:   PetscCheck(mat->cmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Need to provide local to global mapping to matrix first");
6718:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, numRows, rows, PETSC_COPY_VALUES, &is));
6719:   PetscCall(ISLocalToGlobalMappingApplyIS(mat->cmap->mapping, is, &newis));
6720:   PetscCall(ISGetIndices(newis, &newRows));
6721:   PetscUseTypeMethod(mat, zerorowscolumns, numRows, newRows, diag, x, b);
6722:   PetscCall(ISRestoreIndices(newis, &newRows));
6723:   PetscCall(ISDestroy(&newis));
6724:   PetscCall(ISDestroy(&is));
6725:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6726:   PetscFunctionReturn(PETSC_SUCCESS);
6727: }

6729: /*@
6730:   MatZeroRowsColumnsLocalIS - Zeros all entries (except possibly the main diagonal)
6731:   of a set of rows and columns of a matrix; using local numbering of rows.

6733:   Collective

6735:   Input Parameters:
6736: + mat  - the matrix
6737: . is   - index set of rows to remove
6738: . diag - value put in all diagonals of eliminated rows
6739: . x    - optional vector of solutions for zeroed rows (other entries in vector are not used)
6740: - b    - optional vector of right-hand side, that will be adjusted by provided solution

6742:   Level: intermediate

6744:   Notes:
6745:   Before calling `MatZeroRowsColumnsLocalIS()`, the user must first set the
6746:   local-to-global mapping by calling `MatSetLocalToGlobalMapping()`, this is often already set for matrices obtained with `DMCreateMatrix()`.

6748:   See `MatZeroRowsColumns()` for details on how this routine operates.

6750: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6751:           `MatZeroRowsColumnsLocal()`, `MatZeroRows()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
6752: @*/
6753: PetscErrorCode MatZeroRowsColumnsLocalIS(Mat mat, IS is, PetscScalar diag, Vec x, Vec b)
6754: {
6755:   PetscInt        numRows;
6756:   const PetscInt *rows;

6758:   PetscFunctionBegin;
6762:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6763:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6764:   MatCheckPreallocated(mat, 1);

6766:   PetscCall(ISGetLocalSize(is, &numRows));
6767:   PetscCall(ISGetIndices(is, &rows));
6768:   PetscCall(MatZeroRowsColumnsLocal(mat, numRows, rows, diag, x, b));
6769:   PetscCall(ISRestoreIndices(is, &rows));
6770:   PetscFunctionReturn(PETSC_SUCCESS);
6771: }

6773: /*@
6774:   MatGetSize - Returns the numbers of rows and columns in a matrix.

6776:   Not Collective

6778:   Input Parameter:
6779: . mat - the matrix

6781:   Output Parameters:
6782: + m - the number of global rows
6783: - n - the number of global columns

6785:   Level: beginner

6787:   Note:
6788:   Both output parameters can be `NULL` on input.

6790: .seealso: [](ch_matrices), `Mat`, `MatSetSizes()`, `MatGetLocalSize()`
6791: @*/
6792: PetscErrorCode MatGetSize(Mat mat, PetscInt *m, PetscInt *n)
6793: {
6794:   PetscFunctionBegin;
6796:   if (m) *m = mat->rmap->N;
6797:   if (n) *n = mat->cmap->N;
6798:   PetscFunctionReturn(PETSC_SUCCESS);
6799: }

6801: /*@
6802:   MatGetLocalSize - For most matrix formats, excluding `MATELEMENTAL` and `MATSCALAPACK`, Returns the number of local rows and local columns
6803:   of a matrix. For all matrices this is the local size of the left and right vectors as returned by `MatCreateVecs()`.

6805:   Not Collective

6807:   Input Parameter:
6808: . mat - the matrix

6810:   Output Parameters:
6811: + m - the number of local rows, use `NULL` to not obtain this value
6812: - n - the number of local columns, use `NULL` to not obtain this value

6814:   Level: beginner

6816: .seealso: [](ch_matrices), `Mat`, `MatSetSizes()`, `MatGetSize()`
6817: @*/
6818: PetscErrorCode MatGetLocalSize(Mat mat, PetscInt *m, PetscInt *n)
6819: {
6820:   PetscFunctionBegin;
6822:   if (m) PetscAssertPointer(m, 2);
6823:   if (n) PetscAssertPointer(n, 3);
6824:   if (m) *m = mat->rmap->n;
6825:   if (n) *n = mat->cmap->n;
6826:   PetscFunctionReturn(PETSC_SUCCESS);
6827: }

6829: /*@
6830:   MatGetOwnershipRangeColumn - Returns the range of matrix columns associated with rows of a
6831:   vector one multiplies this matrix by that are owned by this processor.

6833:   Not Collective, unless matrix has not been allocated, then collective

6835:   Input Parameter:
6836: . mat - the matrix

6838:   Output Parameters:
6839: + m - the global index of the first local column, use `NULL` to not obtain this value
6840: - n - one more than the global index of the last local column, use `NULL` to not obtain this value

6842:   Level: developer

6844:   Notes:
6845:   If the `Mat` was obtained from a `DM` with `DMCreateMatrix()`, then the range values are determined by the specific `DM`.

6847:   If the `Mat` was created directly the range values are determined by the local size passed to `MatSetSizes()` or `MatCreateAIJ()`.
6848:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

6850:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
6851:   the local values in the matrix.

6853:   Returns the columns of the "diagonal block" for most sparse matrix formats. See [Matrix
6854:   Layouts](sec_matlayout) for details on matrix layouts.

6856: .seealso: [](ch_matrices), `Mat`, `MatGetOwnershipRange()`, `MatGetOwnershipRanges()`, `MatGetOwnershipRangesColumn()`, `PetscLayout`,
6857:           `MatSetSizes()`, `MatCreateAIJ()`, `DMDAGetGhostCorners()`, `DM`
6858: @*/
6859: PetscErrorCode MatGetOwnershipRangeColumn(Mat mat, PetscInt *m, PetscInt *n)
6860: {
6861:   PetscFunctionBegin;
6864:   if (m) PetscAssertPointer(m, 2);
6865:   if (n) PetscAssertPointer(n, 3);
6866:   MatCheckPreallocated(mat, 1);
6867:   if (m) *m = mat->cmap->rstart;
6868:   if (n) *n = mat->cmap->rend;
6869:   PetscFunctionReturn(PETSC_SUCCESS);
6870: }

6872: /*@
6873:   MatGetOwnershipRange - For matrices that own values by row, excludes `MATELEMENTAL` and `MATSCALAPACK`, returns the range of matrix rows owned by
6874:   this MPI process.

6876:   Not Collective

6878:   Input Parameter:
6879: . mat - the matrix

6881:   Output Parameters:
6882: + m - the global index of the first local row, use `NULL` to not obtain this value
6883: - n - one more than the global index of the last local row, use `NULL` to not obtain this value

6885:   Level: beginner

6887:   Notes:
6888:   If the `Mat` was obtained from a `DM` with `DMCreateMatrix()`, then the range values are determined by the specific `DM`.

6890:   If the `Mat` was created directly the range values are determined by the local size passed to `MatSetSizes()` or `MatCreateAIJ()`.
6891:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

6893:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
6894:   the local values in the matrix.

6896:   The high argument is one more than the last element stored locally.

6898:   For all matrices  it returns the range of matrix rows associated with rows of a vector that
6899:   would contain the result of a matrix vector product with this matrix. See [Matrix
6900:   Layouts](sec_matlayout) for details on matrix layouts.

6902: .seealso: [](ch_matrices), `Mat`, `MatGetOwnershipRanges()`, `MatGetOwnershipRangeColumn()`, `MatGetOwnershipRangesColumn()`, `PetscSplitOwnership()`,
6903:           `PetscSplitOwnershipBlock()`, `PetscLayout`, `MatSetSizes()`, `MatCreateAIJ()`, `DMDAGetGhostCorners()`, `DM`
6904: @*/
6905: PetscErrorCode MatGetOwnershipRange(Mat mat, PetscInt *m, PetscInt *n)
6906: {
6907:   PetscFunctionBegin;
6910:   if (m) PetscAssertPointer(m, 2);
6911:   if (n) PetscAssertPointer(n, 3);
6912:   MatCheckPreallocated(mat, 1);
6913:   if (m) *m = mat->rmap->rstart;
6914:   if (n) *n = mat->rmap->rend;
6915:   PetscFunctionReturn(PETSC_SUCCESS);
6916: }

6918: /*@C
6919:   MatGetOwnershipRanges - For matrices that own values by row, excludes `MATELEMENTAL` and
6920:   `MATSCALAPACK`, returns the range of matrix rows owned by each process.

6922:   Not Collective, unless matrix has not been allocated

6924:   Input Parameter:
6925: . mat - the matrix

6927:   Output Parameter:
6928: . ranges - start of each processors portion plus one more than the total length at the end, of length `size` + 1
6929:            where `size` is the number of MPI processes used by `mat`

6931:   Level: beginner

6933:   Notes:
6934:   If the `Mat` was obtained from a `DM` with `DMCreateMatrix()`, then the range values are determined by the specific `DM`.

6936:   If the `Mat` was created directly the range values are determined by the local size passed to `MatSetSizes()` or `MatCreateAIJ()`.
6937:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

6939:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
6940:   the local values in the matrix.

6942:   For all matrices  it returns the ranges of matrix rows associated with rows of a vector that
6943:   would contain the result of a matrix vector product with this matrix. See [Matrix
6944:   Layouts](sec_matlayout) for details on matrix layouts.

6946: .seealso: [](ch_matrices), `Mat`, `MatGetOwnershipRange()`, `MatGetOwnershipRangeColumn()`, `MatGetOwnershipRangesColumn()`, `PetscLayout`,
6947:           `PetscSplitOwnership()`, `PetscSplitOwnershipBlock()`, `MatSetSizes()`, `MatCreateAIJ()`,
6948:           `DMDAGetGhostCorners()`, `DM`
6949: @*/
6950: PetscErrorCode MatGetOwnershipRanges(Mat mat, const PetscInt *ranges[])
6951: {
6952:   PetscFunctionBegin;
6955:   MatCheckPreallocated(mat, 1);
6956:   PetscCall(PetscLayoutGetRanges(mat->rmap, ranges));
6957:   PetscFunctionReturn(PETSC_SUCCESS);
6958: }

6960: /*@C
6961:   MatGetOwnershipRangesColumn - Returns the ranges of matrix columns associated with rows of a
6962:   vector one multiplies this vector by that are owned by each processor.

6964:   Not Collective, unless matrix has not been allocated

6966:   Input Parameter:
6967: . mat - the matrix

6969:   Output Parameter:
6970: . ranges - start of each processors portion plus one more than the total length at the end

6972:   Level: beginner

6974:   Notes:
6975:   If the `Mat` was obtained from a `DM` with `DMCreateMatrix()`, then the range values are determined by the specific `DM`.

6977:   If the `Mat` was created directly the range values are determined by the local size passed to `MatSetSizes()` or `MatCreateAIJ()`.
6978:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

6980:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
6981:   the local values in the matrix.

6983:   Returns the columns of the "diagonal blocks", for most sparse matrix formats. See [Matrix
6984:   Layouts](sec_matlayout) for details on matrix layouts.

6986: .seealso: [](ch_matrices), `Mat`, `MatGetOwnershipRange()`, `MatGetOwnershipRangeColumn()`, `MatGetOwnershipRanges()`,
6987:           `PetscSplitOwnership()`, `PetscSplitOwnershipBlock()`, `PetscLayout`, `MatSetSizes()`, `MatCreateAIJ()`,
6988:           `DMDAGetGhostCorners()`, `DM`
6989: @*/
6990: PetscErrorCode MatGetOwnershipRangesColumn(Mat mat, const PetscInt *ranges[])
6991: {
6992:   PetscFunctionBegin;
6995:   MatCheckPreallocated(mat, 1);
6996:   PetscCall(PetscLayoutGetRanges(mat->cmap, ranges));
6997:   PetscFunctionReturn(PETSC_SUCCESS);
6998: }

7000: /*@
7001:   MatGetOwnershipIS - Get row and column ownership of a matrices' values as index sets.

7003:   Not Collective

7005:   Input Parameter:
7006: . A - matrix

7008:   Output Parameters:
7009: + rows - rows in which this process owns elements, , use `NULL` to not obtain this value
7010: - cols - columns in which this process owns elements, use `NULL` to not obtain this value

7012:   Level: intermediate

7014:   Note:
7015:   You should call `ISDestroy()` on the returned `IS`

7017:   For most matrices, excluding `MATELEMENTAL` and `MATSCALAPACK`, this corresponds to values
7018:   returned by `MatGetOwnershipRange()`, `MatGetOwnershipRangeColumn()`. For `MATELEMENTAL` and
7019:   `MATSCALAPACK` the ownership is more complicated. See [Matrix Layouts](sec_matlayout) for
7020:   details on matrix layouts.

7022: .seealso: [](ch_matrices), `IS`, `Mat`, `MatGetOwnershipRanges()`, `MatSetValues()`, `MATELEMENTAL`, `MATSCALAPACK`
7023: @*/
7024: PetscErrorCode MatGetOwnershipIS(Mat A, IS *rows, IS *cols)
7025: {
7026:   PetscErrorCode (*f)(Mat, IS *, IS *);

7028:   PetscFunctionBegin;
7031:   MatCheckPreallocated(A, 1);
7032:   PetscCall(PetscObjectQueryFunction((PetscObject)A, "MatGetOwnershipIS_C", &f));
7033:   if (f) {
7034:     PetscCall((*f)(A, rows, cols));
7035:   } else { /* Create a standard row-based partition, each process is responsible for ALL columns in their row block */
7036:     if (rows) PetscCall(ISCreateStride(PETSC_COMM_SELF, A->rmap->n, A->rmap->rstart, 1, rows));
7037:     if (cols) PetscCall(ISCreateStride(PETSC_COMM_SELF, A->cmap->N, 0, 1, cols));
7038:   }
7039:   PetscFunctionReturn(PETSC_SUCCESS);
7040: }

7042: /*@
7043:   MatILUFactorSymbolic - Performs symbolic ILU factorization of a matrix obtained with `MatGetFactor()`
7044:   Uses levels of fill only, not drop tolerance. Use `MatLUFactorNumeric()`
7045:   to complete the factorization.

7047:   Collective

7049:   Input Parameters:
7050: + fact - the factorized matrix obtained with `MatGetFactor()`
7051: . mat  - the matrix
7052: . row  - row permutation
7053: . col  - column permutation
7054: - info - structure containing
7055: .vb
7056:       levels - number of levels of fill.
7057:       expected fill - as ratio of original fill.
7058:       1 or 0 - indicating force fill on diagonal (improves robustness for matrices
7059:                 missing diagonal entries)
7060: .ve

7062:   Level: developer

7064:   Notes:
7065:   See [Matrix Factorization](sec_matfactor) for additional information.

7067:   Most users should employ the `KSP` interface for linear solvers
7068:   instead of working directly with matrix algebra routines such as this.
7069:   See, e.g., `KSPCreate()`.

7071:   Uses the definition of level of fill as in Y. Saad, {cite}`saad2003`

7073:   Developer Note:
7074:   The Fortran interface is not autogenerated as the
7075:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

7077: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`
7078:           `MatGetOrdering()`, `MatFactorInfo`
7079: @*/
7080: PetscErrorCode MatILUFactorSymbolic(Mat fact, Mat mat, IS row, IS col, const MatFactorInfo *info)
7081: {
7082:   PetscFunctionBegin;
7087:   PetscAssertPointer(info, 5);
7088:   PetscAssertPointer(fact, 1);
7089:   PetscCheck(info->levels >= 0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Levels of fill negative %" PetscInt_FMT, (PetscInt)info->levels);
7090:   PetscCheck(info->fill >= 1.0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Expected fill less than 1.0 %g", (double)info->fill);
7091:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7092:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7093:   MatCheckPreallocated(mat, 2);

7095:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_ILUFactorSymbolic, mat, row, col, 0));
7096:   PetscUseTypeMethod(fact, ilufactorsymbolic, mat, row, col, info);
7097:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_ILUFactorSymbolic, mat, row, col, 0));
7098:   PetscFunctionReturn(PETSC_SUCCESS);
7099: }

7101: /*@
7102:   MatICCFactorSymbolic - Performs symbolic incomplete
7103:   Cholesky factorization for a symmetric matrix.  Use
7104:   `MatCholeskyFactorNumeric()` to complete the factorization.

7106:   Collective

7108:   Input Parameters:
7109: + fact - the factorized matrix obtained with `MatGetFactor()`
7110: . mat  - the matrix to be factored
7111: . perm - row and column permutation
7112: - info - structure containing
7113: .vb
7114:       levels - number of levels of fill.
7115:       expected fill - as ratio of original fill.
7116: .ve

7118:   Level: developer

7120:   Notes:
7121:   Most users should employ the `KSP` interface for linear solvers
7122:   instead of working directly with matrix algebra routines such as this.
7123:   See, e.g., `KSPCreate()`.

7125:   This uses the definition of level of fill as in Y. Saad {cite}`saad2003`

7127:   Developer Note:
7128:   The Fortran interface is not autogenerated as the
7129:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

7131: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatCholeskyFactorNumeric()`, `MatCholeskyFactor()`, `MatFactorInfo`
7132: @*/
7133: PetscErrorCode MatICCFactorSymbolic(Mat fact, Mat mat, IS perm, const MatFactorInfo *info)
7134: {
7135:   PetscFunctionBegin;
7139:   PetscAssertPointer(info, 4);
7140:   PetscAssertPointer(fact, 1);
7141:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7142:   PetscCheck(info->levels >= 0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Levels negative %" PetscInt_FMT, (PetscInt)info->levels);
7143:   PetscCheck(info->fill >= 1.0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Expected fill less than 1.0 %g", (double)info->fill);
7144:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7145:   MatCheckPreallocated(mat, 2);

7147:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_ICCFactorSymbolic, mat, perm, 0, 0));
7148:   PetscUseTypeMethod(fact, iccfactorsymbolic, mat, perm, info);
7149:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_ICCFactorSymbolic, mat, perm, 0, 0));
7150:   PetscFunctionReturn(PETSC_SUCCESS);
7151: }

7153: /*@C
7154:   MatCreateSubMatrices - Extracts several submatrices from a matrix. If submat
7155:   points to an array of valid matrices, they may be reused to store the new
7156:   submatrices.

7158:   Collective

7160:   Input Parameters:
7161: + mat   - the matrix
7162: . n     - the number of submatrixes to be extracted (on this processor, may be zero)
7163: . irow  - index set of rows to extract
7164: . icol  - index set of columns to extract
7165: - scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

7167:   Output Parameter:
7168: . submat - the array of submatrices

7170:   Level: advanced

7172:   Notes:
7173:   `MatCreateSubMatrices()` can extract ONLY sequential submatrices
7174:   (from both sequential and parallel matrices). Use `MatCreateSubMatrix()`
7175:   to extract a parallel submatrix.

7177:   Some matrix types place restrictions on the row and column
7178:   indices, such as that they be sorted or that they be equal to each other.

7180:   The index sets may not have duplicate entries.

7182:   When extracting submatrices from a parallel matrix, each processor can
7183:   form a different submatrix by setting the rows and columns of its
7184:   individual index sets according to the local submatrix desired.

7186:   When finished using the submatrices, the user should destroy
7187:   them with `MatDestroySubMatrices()`.

7189:   `MAT_REUSE_MATRIX` can only be used when the nonzero structure of the
7190:   original matrix has not changed from that last call to `MatCreateSubMatrices()`.

7192:   This routine creates the matrices in submat; you should NOT create them before
7193:   calling it. It also allocates the array of matrix pointers submat.

7195:   For `MATBAIJ` matrices the index sets must respect the block structure, that is if they
7196:   request one row/column in a block, they must request all rows/columns that are in
7197:   that block. For example, if the block size is 2 you cannot request just row 0 and
7198:   column 0.

7200:   Fortran Note:
7201:   One must pass in as `submat` a `Mat` array of size at least `n`+1.

7203: .seealso: [](ch_matrices), `Mat`, `MatDestroySubMatrices()`, `MatCreateSubMatrix()`, `MatGetRow()`, `MatGetDiagonal()`, `MatReuse`
7204: @*/
7205: PetscErrorCode MatCreateSubMatrices(Mat mat, PetscInt n, const IS irow[], const IS icol[], MatReuse scall, Mat *submat[])
7206: {
7207:   PetscInt  i;
7208:   PetscBool eq;

7210:   PetscFunctionBegin;
7213:   if (n) {
7214:     PetscAssertPointer(irow, 3);
7216:     PetscAssertPointer(icol, 4);
7218:   }
7219:   PetscAssertPointer(submat, 6);
7220:   if (n && scall == MAT_REUSE_MATRIX) {
7221:     PetscAssertPointer(*submat, 6);
7223:   }
7224:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7225:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7226:   MatCheckPreallocated(mat, 1);
7227:   PetscCall(PetscLogEventBegin(MAT_CreateSubMats, mat, 0, 0, 0));
7228:   PetscUseTypeMethod(mat, createsubmatrices, n, irow, icol, scall, submat);
7229:   PetscCall(PetscLogEventEnd(MAT_CreateSubMats, mat, 0, 0, 0));
7230:   for (i = 0; i < n; i++) {
7231:     (*submat)[i]->factortype = MAT_FACTOR_NONE; /* in case in place factorization was previously done on submatrix */
7232:     PetscCall(ISEqualUnsorted(irow[i], icol[i], &eq));
7233:     if (eq) PetscCall(MatPropagateSymmetryOptions(mat, (*submat)[i]));
7234: #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_CUDA) || defined(PETSC_HAVE_HIP)
7235:     if (mat->boundtocpu && mat->bindingpropagates) {
7236:       PetscCall(MatBindToCPU((*submat)[i], PETSC_TRUE));
7237:       PetscCall(MatSetBindingPropagates((*submat)[i], PETSC_TRUE));
7238:     }
7239: #endif
7240:   }
7241:   PetscFunctionReturn(PETSC_SUCCESS);
7242: }

7244: /*@C
7245:   MatCreateSubMatricesMPI - Extracts MPI submatrices across a sub communicator of mat (by pairs of `IS` that may live on subcomms).

7247:   Collective

7249:   Input Parameters:
7250: + mat   - the matrix
7251: . n     - the number of submatrixes to be extracted
7252: . irow  - index set of rows to extract
7253: . icol  - index set of columns to extract
7254: - scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

7256:   Output Parameter:
7257: . submat - the array of submatrices

7259:   Level: advanced

7261:   Note:
7262:   This is used by `PCGASM`

7264: .seealso: [](ch_matrices), `Mat`, `PCGASM`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRow()`, `MatGetDiagonal()`, `MatReuse`
7265: @*/
7266: PetscErrorCode MatCreateSubMatricesMPI(Mat mat, PetscInt n, const IS irow[], const IS icol[], MatReuse scall, Mat *submat[])
7267: {
7268:   PetscInt  i;
7269:   PetscBool eq;

7271:   PetscFunctionBegin;
7274:   if (n) {
7275:     PetscAssertPointer(irow, 3);
7277:     PetscAssertPointer(icol, 4);
7279:   }
7280:   PetscAssertPointer(submat, 6);
7281:   if (n && scall == MAT_REUSE_MATRIX) {
7282:     PetscAssertPointer(*submat, 6);
7284:   }
7285:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7286:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7287:   MatCheckPreallocated(mat, 1);

7289:   PetscCall(PetscLogEventBegin(MAT_CreateSubMats, mat, 0, 0, 0));
7290:   PetscUseTypeMethod(mat, createsubmatricesmpi, n, irow, icol, scall, submat);
7291:   PetscCall(PetscLogEventEnd(MAT_CreateSubMats, mat, 0, 0, 0));
7292:   for (i = 0; i < n; i++) {
7293:     PetscCall(ISEqualUnsorted(irow[i], icol[i], &eq));
7294:     if (eq) PetscCall(MatPropagateSymmetryOptions(mat, (*submat)[i]));
7295:   }
7296:   PetscFunctionReturn(PETSC_SUCCESS);
7297: }

7299: /*@C
7300:   MatDestroyMatrices - Destroys an array of matrices.

7302:   Collective

7304:   Input Parameters:
7305: + n   - the number of local matrices
7306: - mat - the matrices (this is a pointer to the array of matrices)

7308:   Level: advanced

7310:   Notes:
7311:   Frees not only the matrices, but also the array that contains the matrices

7313:   For matrices obtained with  `MatCreateSubMatrices()` use `MatDestroySubMatrices()`

7315:   Fortran Note:
7316:   Does not free the `mat` array.

7318: .seealso: [](ch_matrices), `Mat`, `MatCreateSubMatrices()`, `MatDestroySubMatrices()`
7319: @*/
7320: PetscErrorCode MatDestroyMatrices(PetscInt n, Mat *mat[])
7321: {
7322:   PetscInt i;

7324:   PetscFunctionBegin;
7325:   if (!*mat) PetscFunctionReturn(PETSC_SUCCESS);
7326:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Trying to destroy negative number of matrices %" PetscInt_FMT, n);
7327:   PetscAssertPointer(mat, 2);

7329:   for (i = 0; i < n; i++) PetscCall(MatDestroy(&(*mat)[i]));

7331:   /* memory is allocated even if n = 0 */
7332:   PetscCall(PetscFree(*mat));
7333:   PetscFunctionReturn(PETSC_SUCCESS);
7334: }

7336: /*@C
7337:   MatDestroySubMatrices - Destroys a set of matrices obtained with `MatCreateSubMatrices()`.

7339:   Collective

7341:   Input Parameters:
7342: + n   - the number of local matrices
7343: - mat - the matrices (this is a pointer to the array of matrices, just to match the calling
7344:                        sequence of `MatCreateSubMatrices()`)

7346:   Level: advanced

7348:   Note:
7349:   Frees not only the matrices, but also the array that contains the matrices

7351:   Fortran Note:
7352:   Does not free the `mat` array.

7354: .seealso: [](ch_matrices), `Mat`, `MatCreateSubMatrices()`, `MatDestroyMatrices()`
7355: @*/
7356: PetscErrorCode MatDestroySubMatrices(PetscInt n, Mat *mat[])
7357: {
7358:   Mat mat0;

7360:   PetscFunctionBegin;
7361:   if (!*mat) PetscFunctionReturn(PETSC_SUCCESS);
7362:   /* mat[] is an array of length n+1, see MatCreateSubMatrices_xxx() */
7363:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Trying to destroy negative number of matrices %" PetscInt_FMT, n);
7364:   PetscAssertPointer(mat, 2);

7366:   mat0 = (*mat)[0];
7367:   if (mat0 && mat0->ops->destroysubmatrices) {
7368:     PetscCall((*mat0->ops->destroysubmatrices)(n, mat));
7369:   } else {
7370:     PetscCall(MatDestroyMatrices(n, mat));
7371:   }
7372:   PetscFunctionReturn(PETSC_SUCCESS);
7373: }

7375: /*@
7376:   MatGetSeqNonzeroStructure - Extracts the nonzero structure from a matrix and stores it, in its entirety, on each process

7378:   Collective

7380:   Input Parameter:
7381: . mat - the matrix

7383:   Output Parameter:
7384: . matstruct - the sequential matrix with the nonzero structure of `mat`

7386:   Level: developer

7388: .seealso: [](ch_matrices), `Mat`, `MatDestroySeqNonzeroStructure()`, `MatCreateSubMatrices()`, `MatDestroyMatrices()`
7389: @*/
7390: PetscErrorCode MatGetSeqNonzeroStructure(Mat mat, Mat *matstruct)
7391: {
7392:   PetscFunctionBegin;
7394:   PetscAssertPointer(matstruct, 2);

7397:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7398:   MatCheckPreallocated(mat, 1);

7400:   PetscCall(PetscLogEventBegin(MAT_GetSeqNonzeroStructure, mat, 0, 0, 0));
7401:   PetscUseTypeMethod(mat, getseqnonzerostructure, matstruct);
7402:   PetscCall(PetscLogEventEnd(MAT_GetSeqNonzeroStructure, mat, 0, 0, 0));
7403:   PetscFunctionReturn(PETSC_SUCCESS);
7404: }

7406: /*@C
7407:   MatDestroySeqNonzeroStructure - Destroys matrix obtained with `MatGetSeqNonzeroStructure()`.

7409:   Collective

7411:   Input Parameter:
7412: . mat - the matrix

7414:   Level: advanced

7416:   Note:
7417:   This is not needed, one can just call `MatDestroy()`

7419: .seealso: [](ch_matrices), `Mat`, `MatGetSeqNonzeroStructure()`
7420: @*/
7421: PetscErrorCode MatDestroySeqNonzeroStructure(Mat *mat)
7422: {
7423:   PetscFunctionBegin;
7424:   PetscAssertPointer(mat, 1);
7425:   PetscCall(MatDestroy(mat));
7426:   PetscFunctionReturn(PETSC_SUCCESS);
7427: }

7429: /*@
7430:   MatIncreaseOverlap - Given a set of submatrices indicated by index sets,
7431:   replaces the index sets by larger ones that represent submatrices with
7432:   additional overlap.

7434:   Collective

7436:   Input Parameters:
7437: + mat - the matrix
7438: . n   - the number of index sets
7439: . is  - the array of index sets (these index sets will changed during the call)
7440: - ov  - the additional overlap requested

7442:   Options Database Key:
7443: . -mat_increase_overlap_scalable - use a scalable algorithm to compute the overlap (supported by MPIAIJ matrix)

7445:   Level: developer

7447:   Note:
7448:   The computed overlap preserves the matrix block sizes when the blocks are square.
7449:   That is: if a matrix nonzero for a given block would increase the overlap all columns associated with
7450:   that block are included in the overlap regardless of whether each specific column would increase the overlap.

7452: .seealso: [](ch_matrices), `Mat`, `PCASM`, `MatSetBlockSize()`, `MatIncreaseOverlapSplit()`, `MatCreateSubMatrices()`
7453: @*/
7454: PetscErrorCode MatIncreaseOverlap(Mat mat, PetscInt n, IS is[], PetscInt ov)
7455: {
7456:   PetscInt i, bs, cbs;

7458:   PetscFunctionBegin;
7462:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must have one or more domains, you have %" PetscInt_FMT, n);
7463:   if (n) {
7464:     PetscAssertPointer(is, 3);
7466:   }
7467:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7468:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7469:   MatCheckPreallocated(mat, 1);

7471:   if (!ov || !n) PetscFunctionReturn(PETSC_SUCCESS);
7472:   PetscCall(PetscLogEventBegin(MAT_IncreaseOverlap, mat, 0, 0, 0));
7473:   PetscUseTypeMethod(mat, increaseoverlap, n, is, ov);
7474:   PetscCall(PetscLogEventEnd(MAT_IncreaseOverlap, mat, 0, 0, 0));
7475:   PetscCall(MatGetBlockSizes(mat, &bs, &cbs));
7476:   if (bs == cbs) {
7477:     for (i = 0; i < n; i++) PetscCall(ISSetBlockSize(is[i], bs));
7478:   }
7479:   PetscFunctionReturn(PETSC_SUCCESS);
7480: }

7482: PetscErrorCode MatIncreaseOverlapSplit_Single(Mat, IS *, PetscInt);

7484: /*@
7485:   MatIncreaseOverlapSplit - Given a set of submatrices indicated by index sets across
7486:   a sub communicator, replaces the index sets by larger ones that represent submatrices with
7487:   additional overlap.

7489:   Collective

7491:   Input Parameters:
7492: + mat - the matrix
7493: . n   - the number of index sets
7494: . is  - the array of index sets (these index sets will changed during the call)
7495: - ov  - the additional overlap requested

7497:   `   Options Database Key:
7498: . -mat_increase_overlap_scalable - use a scalable algorithm to compute the overlap (supported by MPIAIJ matrix)

7500:   Level: developer

7502: .seealso: [](ch_matrices), `Mat`, `MatCreateSubMatrices()`, `MatIncreaseOverlap()`
7503: @*/
7504: PetscErrorCode MatIncreaseOverlapSplit(Mat mat, PetscInt n, IS is[], PetscInt ov)
7505: {
7506:   PetscInt i;

7508:   PetscFunctionBegin;
7511:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must have one or more domains, you have %" PetscInt_FMT, n);
7512:   if (n) {
7513:     PetscAssertPointer(is, 3);
7515:   }
7516:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7517:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7518:   MatCheckPreallocated(mat, 1);
7519:   if (!ov) PetscFunctionReturn(PETSC_SUCCESS);
7520:   PetscCall(PetscLogEventBegin(MAT_IncreaseOverlap, mat, 0, 0, 0));
7521:   for (i = 0; i < n; i++) PetscCall(MatIncreaseOverlapSplit_Single(mat, &is[i], ov));
7522:   PetscCall(PetscLogEventEnd(MAT_IncreaseOverlap, mat, 0, 0, 0));
7523:   PetscFunctionReturn(PETSC_SUCCESS);
7524: }

7526: /*@
7527:   MatGetBlockSize - Returns the matrix block size.

7529:   Not Collective

7531:   Input Parameter:
7532: . mat - the matrix

7534:   Output Parameter:
7535: . bs - block size

7537:   Level: intermediate

7539:   Notes:
7540:   Block row formats are `MATBAIJ` and `MATSBAIJ` ALWAYS have square block storage in the matrix.

7542:   If the block size has not been set yet this routine returns 1.

7544: .seealso: [](ch_matrices), `Mat`, `MATBAIJ`, `MATSBAIJ`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSizes()`
7545: @*/
7546: PetscErrorCode MatGetBlockSize(Mat mat, PetscInt *bs)
7547: {
7548:   PetscFunctionBegin;
7550:   PetscAssertPointer(bs, 2);
7551:   *bs = PetscAbs(mat->rmap->bs);
7552:   PetscFunctionReturn(PETSC_SUCCESS);
7553: }

7555: /*@
7556:   MatGetBlockSizes - Returns the matrix block row and column sizes.

7558:   Not Collective

7560:   Input Parameter:
7561: . mat - the matrix

7563:   Output Parameters:
7564: + rbs - row block size
7565: - cbs - column block size

7567:   Level: intermediate

7569:   Notes:
7570:   Block row formats are `MATBAIJ` and `MATSBAIJ` ALWAYS have square block storage in the matrix.
7571:   If you pass a different block size for the columns than the rows, the row block size determines the square block storage.

7573:   If a block size has not been set yet this routine returns 1.

7575: .seealso: [](ch_matrices), `Mat`, `MATBAIJ`, `MATSBAIJ`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSize()`, `MatSetBlockSizes()`
7576: @*/
7577: PetscErrorCode MatGetBlockSizes(Mat mat, PetscInt *rbs, PetscInt *cbs)
7578: {
7579:   PetscFunctionBegin;
7581:   if (rbs) PetscAssertPointer(rbs, 2);
7582:   if (cbs) PetscAssertPointer(cbs, 3);
7583:   if (rbs) *rbs = PetscAbs(mat->rmap->bs);
7584:   if (cbs) *cbs = PetscAbs(mat->cmap->bs);
7585:   PetscFunctionReturn(PETSC_SUCCESS);
7586: }

7588: /*@
7589:   MatSetBlockSize - Sets the matrix block size.

7591:   Logically Collective

7593:   Input Parameters:
7594: + mat - the matrix
7595: - bs  - block size

7597:   Level: intermediate

7599:   Notes:
7600:   Block row formats are `MATBAIJ` and `MATSBAIJ` formats ALWAYS have square block storage in the matrix.
7601:   This must be called before `MatSetUp()` or MatXXXSetPreallocation() (or will default to 1) and the block size cannot be changed later.

7603:   For `MATAIJ` matrix format, this function can be called at a later stage, provided that the specified block size
7604:   is compatible with the matrix local sizes.

7606: .seealso: [](ch_matrices), `Mat`, `MATBAIJ`, `MATSBAIJ`, `MATAIJ`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`, `MatGetBlockSizes()`
7607: @*/
7608: PetscErrorCode MatSetBlockSize(Mat mat, PetscInt bs)
7609: {
7610:   PetscFunctionBegin;
7613:   PetscCall(MatSetBlockSizes(mat, bs, bs));
7614:   PetscFunctionReturn(PETSC_SUCCESS);
7615: }

7617: typedef struct {
7618:   PetscInt         n;
7619:   IS              *is;
7620:   Mat             *mat;
7621:   PetscObjectState nonzerostate;
7622:   Mat              C;
7623: } EnvelopeData;

7625: static PetscErrorCode EnvelopeDataDestroy(void *ptr)
7626: {
7627:   EnvelopeData *edata = (EnvelopeData *)ptr;

7629:   PetscFunctionBegin;
7630:   for (PetscInt i = 0; i < edata->n; i++) PetscCall(ISDestroy(&edata->is[i]));
7631:   PetscCall(PetscFree(edata->is));
7632:   PetscCall(PetscFree(edata));
7633:   PetscFunctionReturn(PETSC_SUCCESS);
7634: }

7636: /*@
7637:   MatComputeVariableBlockEnvelope - Given a matrix whose nonzeros are in blocks along the diagonal this computes and stores
7638:   the sizes of these blocks in the matrix. An individual block may lie over several processes.

7640:   Collective

7642:   Input Parameter:
7643: . mat - the matrix

7645:   Level: intermediate

7647:   Notes:
7648:   There can be zeros within the blocks

7650:   The blocks can overlap between processes, including laying on more than two processes

7652: .seealso: [](ch_matrices), `Mat`, `MatInvertVariableBlockEnvelope()`, `MatSetVariableBlockSizes()`
7653: @*/
7654: PetscErrorCode MatComputeVariableBlockEnvelope(Mat mat)
7655: {
7656:   PetscInt           n, *sizes, *starts, i = 0, env = 0, tbs = 0, lblocks = 0, rstart, II, ln = 0, cnt = 0, cstart, cend;
7657:   PetscInt          *diag, *odiag, sc;
7658:   VecScatter         scatter;
7659:   PetscScalar       *seqv;
7660:   const PetscScalar *parv;
7661:   const PetscInt    *ia, *ja;
7662:   PetscBool          set, flag, done;
7663:   Mat                AA = mat, A;
7664:   MPI_Comm           comm;
7665:   PetscMPIInt        rank, size, tag;
7666:   MPI_Status         status;
7667:   PetscContainer     container;
7668:   EnvelopeData      *edata;
7669:   Vec                seq, par;
7670:   IS                 isglobal;

7672:   PetscFunctionBegin;
7674:   PetscCall(MatIsSymmetricKnown(mat, &set, &flag));
7675:   if (!set || !flag) {
7676:     /* TODO: only needs nonzero structure of transpose */
7677:     PetscCall(MatTranspose(mat, MAT_INITIAL_MATRIX, &AA));
7678:     PetscCall(MatAXPY(AA, 1.0, mat, DIFFERENT_NONZERO_PATTERN));
7679:   }
7680:   PetscCall(MatAIJGetLocalMat(AA, &A));
7681:   PetscCall(MatGetRowIJ(A, 0, PETSC_FALSE, PETSC_FALSE, &n, &ia, &ja, &done));
7682:   PetscCheck(done, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Unable to get IJ structure from matrix");

7684:   PetscCall(MatGetLocalSize(mat, &n, NULL));
7685:   PetscCall(PetscObjectGetNewTag((PetscObject)mat, &tag));
7686:   PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
7687:   PetscCallMPI(MPI_Comm_size(comm, &size));
7688:   PetscCallMPI(MPI_Comm_rank(comm, &rank));

7690:   PetscCall(PetscMalloc2(n, &sizes, n, &starts));

7692:   if (rank > 0) {
7693:     PetscCallMPI(MPI_Recv(&env, 1, MPIU_INT, rank - 1, tag, comm, &status));
7694:     PetscCallMPI(MPI_Recv(&tbs, 1, MPIU_INT, rank - 1, tag, comm, &status));
7695:   }
7696:   PetscCall(MatGetOwnershipRange(mat, &rstart, NULL));
7697:   for (i = 0; i < n; i++) {
7698:     env = PetscMax(env, ja[ia[i + 1] - 1]);
7699:     II  = rstart + i;
7700:     if (env == II) {
7701:       starts[lblocks]  = tbs;
7702:       sizes[lblocks++] = 1 + II - tbs;
7703:       tbs              = 1 + II;
7704:     }
7705:   }
7706:   if (rank < size - 1) {
7707:     PetscCallMPI(MPI_Send(&env, 1, MPIU_INT, rank + 1, tag, comm));
7708:     PetscCallMPI(MPI_Send(&tbs, 1, MPIU_INT, rank + 1, tag, comm));
7709:   }

7711:   PetscCall(MatRestoreRowIJ(A, 0, PETSC_FALSE, PETSC_FALSE, &n, &ia, &ja, &done));
7712:   if (!set || !flag) PetscCall(MatDestroy(&AA));
7713:   PetscCall(MatDestroy(&A));

7715:   PetscCall(PetscNew(&edata));
7716:   PetscCall(MatGetNonzeroState(mat, &edata->nonzerostate));
7717:   edata->n = lblocks;
7718:   /* create IS needed for extracting blocks from the original matrix */
7719:   PetscCall(PetscMalloc1(lblocks, &edata->is));
7720:   for (PetscInt i = 0; i < lblocks; i++) PetscCall(ISCreateStride(PETSC_COMM_SELF, sizes[i], starts[i], 1, &edata->is[i]));

7722:   /* Create the resulting inverse matrix nonzero structure with preallocation information */
7723:   PetscCall(MatCreate(PetscObjectComm((PetscObject)mat), &edata->C));
7724:   PetscCall(MatSetSizes(edata->C, mat->rmap->n, mat->cmap->n, mat->rmap->N, mat->cmap->N));
7725:   PetscCall(MatSetBlockSizesFromMats(edata->C, mat, mat));
7726:   PetscCall(MatSetType(edata->C, MATAIJ));

7728:   /* Communicate the start and end of each row, from each block to the correct rank */
7729:   /* TODO: Use PetscSF instead of VecScatter */
7730:   for (PetscInt i = 0; i < lblocks; i++) ln += sizes[i];
7731:   PetscCall(VecCreateSeq(PETSC_COMM_SELF, 2 * ln, &seq));
7732:   PetscCall(VecGetArrayWrite(seq, &seqv));
7733:   for (PetscInt i = 0; i < lblocks; i++) {
7734:     for (PetscInt j = 0; j < sizes[i]; j++) {
7735:       seqv[cnt]     = starts[i];
7736:       seqv[cnt + 1] = starts[i] + sizes[i];
7737:       cnt += 2;
7738:     }
7739:   }
7740:   PetscCall(VecRestoreArrayWrite(seq, &seqv));
7741:   PetscCallMPI(MPI_Scan(&cnt, &sc, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)mat)));
7742:   sc -= cnt;
7743:   PetscCall(VecCreateMPI(PetscObjectComm((PetscObject)mat), 2 * mat->rmap->n, 2 * mat->rmap->N, &par));
7744:   PetscCall(ISCreateStride(PETSC_COMM_SELF, cnt, sc, 1, &isglobal));
7745:   PetscCall(VecScatterCreate(seq, NULL, par, isglobal, &scatter));
7746:   PetscCall(ISDestroy(&isglobal));
7747:   PetscCall(VecScatterBegin(scatter, seq, par, INSERT_VALUES, SCATTER_FORWARD));
7748:   PetscCall(VecScatterEnd(scatter, seq, par, INSERT_VALUES, SCATTER_FORWARD));
7749:   PetscCall(VecScatterDestroy(&scatter));
7750:   PetscCall(VecDestroy(&seq));
7751:   PetscCall(MatGetOwnershipRangeColumn(mat, &cstart, &cend));
7752:   PetscCall(PetscMalloc2(mat->rmap->n, &diag, mat->rmap->n, &odiag));
7753:   PetscCall(VecGetArrayRead(par, &parv));
7754:   cnt = 0;
7755:   PetscCall(MatGetSize(mat, NULL, &n));
7756:   for (PetscInt i = 0; i < mat->rmap->n; i++) {
7757:     PetscInt start, end, d = 0, od = 0;

7759:     start = (PetscInt)PetscRealPart(parv[cnt]);
7760:     end   = (PetscInt)PetscRealPart(parv[cnt + 1]);
7761:     cnt += 2;

7763:     if (start < cstart) {
7764:       od += cstart - start + n - cend;
7765:       d += cend - cstart;
7766:     } else if (start < cend) {
7767:       od += n - cend;
7768:       d += cend - start;
7769:     } else od += n - start;
7770:     if (end <= cstart) {
7771:       od -= cstart - end + n - cend;
7772:       d -= cend - cstart;
7773:     } else if (end < cend) {
7774:       od -= n - cend;
7775:       d -= cend - end;
7776:     } else od -= n - end;

7778:     odiag[i] = od;
7779:     diag[i]  = d;
7780:   }
7781:   PetscCall(VecRestoreArrayRead(par, &parv));
7782:   PetscCall(VecDestroy(&par));
7783:   PetscCall(MatXAIJSetPreallocation(edata->C, mat->rmap->bs, diag, odiag, NULL, NULL));
7784:   PetscCall(PetscFree2(diag, odiag));
7785:   PetscCall(PetscFree2(sizes, starts));

7787:   PetscCall(PetscContainerCreate(PETSC_COMM_SELF, &container));
7788:   PetscCall(PetscContainerSetPointer(container, edata));
7789:   PetscCall(PetscContainerSetUserDestroy(container, (PetscErrorCode (*)(void *))EnvelopeDataDestroy));
7790:   PetscCall(PetscObjectCompose((PetscObject)mat, "EnvelopeData", (PetscObject)container));
7791:   PetscCall(PetscObjectDereference((PetscObject)container));
7792:   PetscFunctionReturn(PETSC_SUCCESS);
7793: }

7795: /*@
7796:   MatInvertVariableBlockEnvelope - set matrix C to be the inverted block diagonal of matrix A

7798:   Collective

7800:   Input Parameters:
7801: + A     - the matrix
7802: - reuse - indicates if the `C` matrix was obtained from a previous call to this routine

7804:   Output Parameter:
7805: . C - matrix with inverted block diagonal of `A`

7807:   Level: advanced

7809:   Note:
7810:   For efficiency the matrix `A` should have all the nonzero entries clustered in smallish blocks along the diagonal.

7812: .seealso: [](ch_matrices), `Mat`, `MatInvertBlockDiagonal()`, `MatComputeBlockDiagonal()`
7813: @*/
7814: PetscErrorCode MatInvertVariableBlockEnvelope(Mat A, MatReuse reuse, Mat *C)
7815: {
7816:   PetscContainer   container;
7817:   EnvelopeData    *edata;
7818:   PetscObjectState nonzerostate;

7820:   PetscFunctionBegin;
7821:   PetscCall(PetscObjectQuery((PetscObject)A, "EnvelopeData", (PetscObject *)&container));
7822:   if (!container) {
7823:     PetscCall(MatComputeVariableBlockEnvelope(A));
7824:     PetscCall(PetscObjectQuery((PetscObject)A, "EnvelopeData", (PetscObject *)&container));
7825:   }
7826:   PetscCall(PetscContainerGetPointer(container, (void **)&edata));
7827:   PetscCall(MatGetNonzeroState(A, &nonzerostate));
7828:   PetscCheck(nonzerostate <= edata->nonzerostate, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot handle changes to matrix nonzero structure");
7829:   PetscCheck(reuse != MAT_REUSE_MATRIX || *C == edata->C, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "C matrix must be the same as previously output");

7831:   PetscCall(MatCreateSubMatrices(A, edata->n, edata->is, edata->is, MAT_INITIAL_MATRIX, &edata->mat));
7832:   *C = edata->C;

7834:   for (PetscInt i = 0; i < edata->n; i++) {
7835:     Mat          D;
7836:     PetscScalar *dvalues;

7838:     PetscCall(MatConvert(edata->mat[i], MATSEQDENSE, MAT_INITIAL_MATRIX, &D));
7839:     PetscCall(MatSetOption(*C, MAT_ROW_ORIENTED, PETSC_FALSE));
7840:     PetscCall(MatSeqDenseInvert(D));
7841:     PetscCall(MatDenseGetArray(D, &dvalues));
7842:     PetscCall(MatSetValuesIS(*C, edata->is[i], edata->is[i], dvalues, INSERT_VALUES));
7843:     PetscCall(MatDestroy(&D));
7844:   }
7845:   PetscCall(MatDestroySubMatrices(edata->n, &edata->mat));
7846:   PetscCall(MatAssemblyBegin(*C, MAT_FINAL_ASSEMBLY));
7847:   PetscCall(MatAssemblyEnd(*C, MAT_FINAL_ASSEMBLY));
7848:   PetscFunctionReturn(PETSC_SUCCESS);
7849: }

7851: /*@
7852:   MatSetVariableBlockSizes - Sets diagonal point-blocks of the matrix that need not be of the same size

7854:   Not Collective

7856:   Input Parameters:
7857: + mat     - the matrix
7858: . nblocks - the number of blocks on this process, each block can only exist on a single process
7859: - bsizes  - the block sizes

7861:   Level: intermediate

7863:   Notes:
7864:   Currently used by `PCVPBJACOBI` for `MATAIJ` matrices

7866:   Each variable point-block set of degrees of freedom must live on a single MPI process. That is a point block cannot straddle two MPI processes.

7868: .seealso: [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`, `MatGetBlockSizes()`, `MatGetVariableBlockSizes()`,
7869:           `MatComputeVariableBlockEnvelope()`, `PCVPBJACOBI`
7870: @*/
7871: PetscErrorCode MatSetVariableBlockSizes(Mat mat, PetscInt nblocks, const PetscInt bsizes[])
7872: {
7873:   PetscInt ncnt = 0, nlocal;

7875:   PetscFunctionBegin;
7877:   PetscCall(MatGetLocalSize(mat, &nlocal, NULL));
7878:   PetscCheck(nblocks >= 0 && nblocks <= nlocal, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Number of local blocks %" PetscInt_FMT " is not in [0, %" PetscInt_FMT "]", nblocks, nlocal);
7879:   for (PetscInt i = 0; i < nblocks; i++) ncnt += bsizes[i];
7880:   PetscCheck(ncnt == nlocal, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Sum of local block sizes %" PetscInt_FMT " does not equal local size of matrix %" PetscInt_FMT, ncnt, nlocal);
7881:   PetscCall(PetscFree(mat->bsizes));
7882:   mat->nblocks = nblocks;
7883:   PetscCall(PetscMalloc1(nblocks, &mat->bsizes));
7884:   PetscCall(PetscArraycpy(mat->bsizes, bsizes, nblocks));
7885:   PetscFunctionReturn(PETSC_SUCCESS);
7886: }

7888: /*@C
7889:   MatGetVariableBlockSizes - Gets a diagonal blocks of the matrix that need not be of the same size

7891:   Not Collective; No Fortran Support

7893:   Input Parameter:
7894: . mat - the matrix

7896:   Output Parameters:
7897: + nblocks - the number of blocks on this process
7898: - bsizes  - the block sizes

7900:   Level: intermediate

7902: .seealso: [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`, `MatGetBlockSizes()`, `MatSetVariableBlockSizes()`, `MatComputeVariableBlockEnvelope()`
7903: @*/
7904: PetscErrorCode MatGetVariableBlockSizes(Mat mat, PetscInt *nblocks, const PetscInt *bsizes[])
7905: {
7906:   PetscFunctionBegin;
7908:   if (nblocks) *nblocks = mat->nblocks;
7909:   if (bsizes) *bsizes = mat->bsizes;
7910:   PetscFunctionReturn(PETSC_SUCCESS);
7911: }

7913: /*@
7914:   MatSetBlockSizes - Sets the matrix block row and column sizes.

7916:   Logically Collective

7918:   Input Parameters:
7919: + mat - the matrix
7920: . rbs - row block size
7921: - cbs - column block size

7923:   Level: intermediate

7925:   Notes:
7926:   Block row formats are `MATBAIJ` and  `MATSBAIJ`. These formats ALWAYS have square block storage in the matrix.
7927:   If you pass a different block size for the columns than the rows, the row block size determines the square block storage.
7928:   This must be called before `MatSetUp()` or MatXXXSetPreallocation() (or will default to 1) and the block size cannot be changed later.

7930:   For `MATAIJ` matrix this function can be called at a later stage, provided that the specified block sizes
7931:   are compatible with the matrix local sizes.

7933:   The row and column block size determine the blocksize of the "row" and "column" vectors returned by `MatCreateVecs()`.

7935: .seealso: [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSize()`, `MatGetBlockSizes()`
7936: @*/
7937: PetscErrorCode MatSetBlockSizes(Mat mat, PetscInt rbs, PetscInt cbs)
7938: {
7939:   PetscFunctionBegin;
7943:   PetscTryTypeMethod(mat, setblocksizes, rbs, cbs);
7944:   if (mat->rmap->refcnt) {
7945:     ISLocalToGlobalMapping l2g  = NULL;
7946:     PetscLayout            nmap = NULL;

7948:     PetscCall(PetscLayoutDuplicate(mat->rmap, &nmap));
7949:     if (mat->rmap->mapping) PetscCall(ISLocalToGlobalMappingDuplicate(mat->rmap->mapping, &l2g));
7950:     PetscCall(PetscLayoutDestroy(&mat->rmap));
7951:     mat->rmap          = nmap;
7952:     mat->rmap->mapping = l2g;
7953:   }
7954:   if (mat->cmap->refcnt) {
7955:     ISLocalToGlobalMapping l2g  = NULL;
7956:     PetscLayout            nmap = NULL;

7958:     PetscCall(PetscLayoutDuplicate(mat->cmap, &nmap));
7959:     if (mat->cmap->mapping) PetscCall(ISLocalToGlobalMappingDuplicate(mat->cmap->mapping, &l2g));
7960:     PetscCall(PetscLayoutDestroy(&mat->cmap));
7961:     mat->cmap          = nmap;
7962:     mat->cmap->mapping = l2g;
7963:   }
7964:   PetscCall(PetscLayoutSetBlockSize(mat->rmap, rbs));
7965:   PetscCall(PetscLayoutSetBlockSize(mat->cmap, cbs));
7966:   PetscFunctionReturn(PETSC_SUCCESS);
7967: }

7969: /*@
7970:   MatSetBlockSizesFromMats - Sets the matrix block row and column sizes to match a pair of matrices

7972:   Logically Collective

7974:   Input Parameters:
7975: + mat     - the matrix
7976: . fromRow - matrix from which to copy row block size
7977: - fromCol - matrix from which to copy column block size (can be same as fromRow)

7979:   Level: developer

7981: .seealso: [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`
7982: @*/
7983: PetscErrorCode MatSetBlockSizesFromMats(Mat mat, Mat fromRow, Mat fromCol)
7984: {
7985:   PetscFunctionBegin;
7989:   if (fromRow->rmap->bs > 0) PetscCall(PetscLayoutSetBlockSize(mat->rmap, fromRow->rmap->bs));
7990:   if (fromCol->cmap->bs > 0) PetscCall(PetscLayoutSetBlockSize(mat->cmap, fromCol->cmap->bs));
7991:   PetscFunctionReturn(PETSC_SUCCESS);
7992: }

7994: /*@
7995:   MatResidual - Default routine to calculate the residual r = b - Ax

7997:   Collective

7999:   Input Parameters:
8000: + mat - the matrix
8001: . b   - the right-hand-side
8002: - x   - the approximate solution

8004:   Output Parameter:
8005: . r - location to store the residual

8007:   Level: developer

8009: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatMultAdd()`, `PCMGSetResidual()`
8010: @*/
8011: PetscErrorCode MatResidual(Mat mat, Vec b, Vec x, Vec r)
8012: {
8013:   PetscFunctionBegin;
8019:   MatCheckPreallocated(mat, 1);
8020:   PetscCall(PetscLogEventBegin(MAT_Residual, mat, 0, 0, 0));
8021:   if (!mat->ops->residual) {
8022:     PetscCall(MatMult(mat, x, r));
8023:     PetscCall(VecAYPX(r, -1.0, b));
8024:   } else {
8025:     PetscUseTypeMethod(mat, residual, b, x, r);
8026:   }
8027:   PetscCall(PetscLogEventEnd(MAT_Residual, mat, 0, 0, 0));
8028:   PetscFunctionReturn(PETSC_SUCCESS);
8029: }

8031: /*MC
8032:     MatGetRowIJF90 - Obtains the compressed row storage i and j indices for the local rows of a sparse matrix

8034:     Synopsis:
8035:     MatGetRowIJF90(Mat A, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt n, {PetscInt, pointer :: ia(:)}, {PetscInt, pointer :: ja(:)}, PetscBool done,integer ierr)

8037:     Not Collective

8039:     Input Parameters:
8040: +   A - the matrix
8041: .   shift -  0 or 1 indicating we want the indices starting at 0 or 1
8042: .   symmetric - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized
8043: -   inodecompressed - `PETSC_TRUE` or `PETSC_FALSE`  indicating if the nonzero structure of the
8044:                  inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8045:                  always used.

8047:     Output Parameters:
8048: +   n - number of local rows in the (possibly compressed) matrix
8049: .   ia - the row pointers; that is ia[0] = 0, ia[row] = ia[row-1] + number of elements in that row of the matrix
8050: .   ja - the column indices
8051: -   done - indicates if the routine actually worked and returned appropriate ia[] and ja[] arrays; callers
8052:            are responsible for handling the case when done == `PETSC_FALSE` and ia and ja are not set

8054:     Level: developer

8056:     Note:
8057:     Use  `MatRestoreRowIJF90()` when you no longer need access to the data

8059: .seealso: [](ch_matrices), [](sec_fortranarrays), `Mat`, `MATMPIAIJ`, `MatGetRowIJ()`, `MatRestoreRowIJ()`, `MatRestoreRowIJF90()`
8060: M*/

8062: /*MC
8063:     MatRestoreRowIJF90 - restores the compressed row storage i and j indices for the local rows of a sparse matrix obtained with `MatGetRowIJF90()`

8065:     Synopsis:
8066:     MatRestoreRowIJF90(Mat A, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt n, {PetscInt, pointer :: ia(:)}, {PetscInt, pointer :: ja(:)}, PetscBool done,integer ierr)

8068:     Not Collective

8070:     Input Parameters:
8071: +   A - the  matrix
8072: .   shift -  0 or 1 indicating we want the indices starting at 0 or 1
8073: .   symmetric - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized
8074:     inodecompressed - `PETSC_TRUE` or `PETSC_FALSE`  indicating if the nonzero structure of the
8075:                  inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8076:                  always used.
8077: .   n - number of local rows in the (possibly compressed) matrix
8078: .   ia - the row pointers; that is ia[0] = 0, ia[row] = ia[row-1] + number of elements in that row of the matrix
8079: .   ja - the column indices
8080: -   done - indicates if the routine actually worked and returned appropriate ia[] and ja[] arrays; callers
8081:            are responsible for handling the case when done == `PETSC_FALSE` and ia and ja are not set

8083:     Level: developer

8085: .seealso: [](ch_matrices), [](sec_fortranarrays), `Mat`, `MATMPIAIJ`, `MatGetRowIJ()`, `MatRestoreRowIJ()`, `MatGetRowIJF90()`
8086: M*/

8088: /*@C
8089:   MatGetRowIJ - Returns the compressed row storage i and j indices for the local rows of a sparse matrix

8091:   Collective

8093:   Input Parameters:
8094: + mat             - the matrix
8095: . shift           - 0 or 1 indicating we want the indices starting at 0 or 1
8096: . symmetric       - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized
8097: - inodecompressed - `PETSC_TRUE` or `PETSC_FALSE`  indicating if the nonzero structure of the
8098:                  inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8099:                  always used.

8101:   Output Parameters:
8102: + n    - number of local rows in the (possibly compressed) matrix, use `NULL` if not needed
8103: . ia   - the row pointers; that is ia[0] = 0, ia[row] = ia[row-1] + number of elements in that row of the matrix, use `NULL` if not needed
8104: . ja   - the column indices, use `NULL` if not needed
8105: - done - indicates if the routine actually worked and returned appropriate ia[] and ja[] arrays; callers
8106:            are responsible for handling the case when done == `PETSC_FALSE` and ia and ja are not set

8108:   Level: developer

8110:   Notes:
8111:   You CANNOT change any of the ia[] or ja[] values.

8113:   Use `MatRestoreRowIJ()` when you are finished accessing the ia[] and ja[] values.

8115:   Fortran Notes:
8116:   Use
8117: .vb
8118:     PetscInt, pointer :: ia(:),ja(:)
8119:     call MatGetRowIJF90(mat,shift,symmetric,inodecompressed,n,ia,ja,done,ierr)
8120:     ! Access the ith and jth entries via ia(i) and ja(j)
8121: .ve

8123:   `MatGetRowIJ()` Fortran binding is deprecated (since PETSc 3.19), use `MatGetRowIJF90()`

8125: .seealso: [](ch_matrices), `Mat`, `MATAIJ`, `MatGetRowIJF90()`, `MatGetColumnIJ()`, `MatRestoreRowIJ()`, `MatSeqAIJGetArray()`
8126: @*/
8127: PetscErrorCode MatGetRowIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
8128: {
8129:   PetscFunctionBegin;
8132:   if (n) PetscAssertPointer(n, 5);
8133:   if (ia) PetscAssertPointer(ia, 6);
8134:   if (ja) PetscAssertPointer(ja, 7);
8135:   if (done) PetscAssertPointer(done, 8);
8136:   MatCheckPreallocated(mat, 1);
8137:   if (!mat->ops->getrowij && done) *done = PETSC_FALSE;
8138:   else {
8139:     if (done) *done = PETSC_TRUE;
8140:     PetscCall(PetscLogEventBegin(MAT_GetRowIJ, mat, 0, 0, 0));
8141:     PetscUseTypeMethod(mat, getrowij, shift, symmetric, inodecompressed, n, ia, ja, done);
8142:     PetscCall(PetscLogEventEnd(MAT_GetRowIJ, mat, 0, 0, 0));
8143:   }
8144:   PetscFunctionReturn(PETSC_SUCCESS);
8145: }

8147: /*@C
8148:   MatGetColumnIJ - Returns the compressed column storage i and j indices for sequential matrices.

8150:   Collective

8152:   Input Parameters:
8153: + mat             - the matrix
8154: . shift           - 1 or zero indicating we want the indices starting at 0 or 1
8155: . symmetric       - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be
8156:                 symmetrized
8157: . inodecompressed - `PETSC_TRUE` or `PETSC_FALSE` indicating if the nonzero structure of the
8158:                  inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8159:                  always used.
8160: . n               - number of columns in the (possibly compressed) matrix
8161: . ia              - the column pointers; that is ia[0] = 0, ia[col] = i[col-1] + number of elements in that col of the matrix
8162: - ja              - the row indices

8164:   Output Parameter:
8165: . done - `PETSC_TRUE` or `PETSC_FALSE`, indicating whether the values have been returned

8167:   Level: developer

8169: .seealso: [](ch_matrices), `Mat`, `MatGetRowIJ()`, `MatRestoreColumnIJ()`
8170: @*/
8171: PetscErrorCode MatGetColumnIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
8172: {
8173:   PetscFunctionBegin;
8176:   PetscAssertPointer(n, 5);
8177:   if (ia) PetscAssertPointer(ia, 6);
8178:   if (ja) PetscAssertPointer(ja, 7);
8179:   PetscAssertPointer(done, 8);
8180:   MatCheckPreallocated(mat, 1);
8181:   if (!mat->ops->getcolumnij) *done = PETSC_FALSE;
8182:   else {
8183:     *done = PETSC_TRUE;
8184:     PetscUseTypeMethod(mat, getcolumnij, shift, symmetric, inodecompressed, n, ia, ja, done);
8185:   }
8186:   PetscFunctionReturn(PETSC_SUCCESS);
8187: }

8189: /*@C
8190:   MatRestoreRowIJ - Call after you are completed with the ia,ja indices obtained with `MatGetRowIJ()`.

8192:   Collective

8194:   Input Parameters:
8195: + mat             - the matrix
8196: . shift           - 1 or zero indicating we want the indices starting at 0 or 1
8197: . symmetric       - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized
8198: . inodecompressed - `PETSC_TRUE` or `PETSC_FALSE` indicating if the nonzero structure of the
8199:                     inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8200:                     always used.
8201: . n               - size of (possibly compressed) matrix
8202: . ia              - the row pointers
8203: - ja              - the column indices

8205:   Output Parameter:
8206: . done - `PETSC_TRUE` or `PETSC_FALSE` indicated that the values have been returned

8208:   Level: developer

8210:   Note:
8211:   This routine zeros out `n`, `ia`, and `ja`. This is to prevent accidental
8212:   us of the array after it has been restored. If you pass `NULL`, it will
8213:   not zero the pointers.  Use of ia or ja after `MatRestoreRowIJ()` is invalid.

8215:   Fortran Note:
8216:   `MatRestoreRowIJ()` Fortran binding is deprecated (since PETSc 3.19), use `MatRestoreRowIJF90()`

8218: .seealso: [](ch_matrices), `Mat`, `MatGetRowIJ()`, `MatRestoreRowIJF90()`, `MatRestoreColumnIJ()`
8219: @*/
8220: PetscErrorCode MatRestoreRowIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
8221: {
8222:   PetscFunctionBegin;
8225:   if (ia) PetscAssertPointer(ia, 6);
8226:   if (ja) PetscAssertPointer(ja, 7);
8227:   if (done) PetscAssertPointer(done, 8);
8228:   MatCheckPreallocated(mat, 1);

8230:   if (!mat->ops->restorerowij && done) *done = PETSC_FALSE;
8231:   else {
8232:     if (done) *done = PETSC_TRUE;
8233:     PetscUseTypeMethod(mat, restorerowij, shift, symmetric, inodecompressed, n, ia, ja, done);
8234:     if (n) *n = 0;
8235:     if (ia) *ia = NULL;
8236:     if (ja) *ja = NULL;
8237:   }
8238:   PetscFunctionReturn(PETSC_SUCCESS);
8239: }

8241: /*@C
8242:   MatRestoreColumnIJ - Call after you are completed with the ia,ja indices obtained with `MatGetColumnIJ()`.

8244:   Collective

8246:   Input Parameters:
8247: + mat             - the matrix
8248: . shift           - 1 or zero indicating we want the indices starting at 0 or 1
8249: . symmetric       - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized
8250: - inodecompressed - `PETSC_TRUE` or `PETSC_FALSE` indicating if the nonzero structure of the
8251:                     inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8252:                     always used.

8254:   Output Parameters:
8255: + n    - size of (possibly compressed) matrix
8256: . ia   - the column pointers
8257: . ja   - the row indices
8258: - done - `PETSC_TRUE` or `PETSC_FALSE` indicated that the values have been returned

8260:   Level: developer

8262: .seealso: [](ch_matrices), `Mat`, `MatGetColumnIJ()`, `MatRestoreRowIJ()`
8263: @*/
8264: PetscErrorCode MatRestoreColumnIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
8265: {
8266:   PetscFunctionBegin;
8269:   if (ia) PetscAssertPointer(ia, 6);
8270:   if (ja) PetscAssertPointer(ja, 7);
8271:   PetscAssertPointer(done, 8);
8272:   MatCheckPreallocated(mat, 1);

8274:   if (!mat->ops->restorecolumnij) *done = PETSC_FALSE;
8275:   else {
8276:     *done = PETSC_TRUE;
8277:     PetscUseTypeMethod(mat, restorecolumnij, shift, symmetric, inodecompressed, n, ia, ja, done);
8278:     if (n) *n = 0;
8279:     if (ia) *ia = NULL;
8280:     if (ja) *ja = NULL;
8281:   }
8282:   PetscFunctionReturn(PETSC_SUCCESS);
8283: }

8285: /*@
8286:   MatColoringPatch - Used inside matrix coloring routines that use `MatGetRowIJ()` and/or
8287:   `MatGetColumnIJ()`.

8289:   Collective

8291:   Input Parameters:
8292: + mat        - the matrix
8293: . ncolors    - maximum color value
8294: . n          - number of entries in colorarray
8295: - colorarray - array indicating color for each column

8297:   Output Parameter:
8298: . iscoloring - coloring generated using colorarray information

8300:   Level: developer

8302: .seealso: [](ch_matrices), `Mat`, `MatGetRowIJ()`, `MatGetColumnIJ()`
8303: @*/
8304: PetscErrorCode MatColoringPatch(Mat mat, PetscInt ncolors, PetscInt n, ISColoringValue colorarray[], ISColoring *iscoloring)
8305: {
8306:   PetscFunctionBegin;
8309:   PetscAssertPointer(colorarray, 4);
8310:   PetscAssertPointer(iscoloring, 5);
8311:   MatCheckPreallocated(mat, 1);

8313:   if (!mat->ops->coloringpatch) {
8314:     PetscCall(ISColoringCreate(PetscObjectComm((PetscObject)mat), ncolors, n, colorarray, PETSC_OWN_POINTER, iscoloring));
8315:   } else {
8316:     PetscUseTypeMethod(mat, coloringpatch, ncolors, n, colorarray, iscoloring);
8317:   }
8318:   PetscFunctionReturn(PETSC_SUCCESS);
8319: }

8321: /*@
8322:   MatSetUnfactored - Resets a factored matrix to be treated as unfactored.

8324:   Logically Collective

8326:   Input Parameter:
8327: . mat - the factored matrix to be reset

8329:   Level: developer

8331:   Notes:
8332:   This routine should be used only with factored matrices formed by in-place
8333:   factorization via ILU(0) (or by in-place LU factorization for the `MATSEQDENSE`
8334:   format).  This option can save memory, for example, when solving nonlinear
8335:   systems with a matrix-free Newton-Krylov method and a matrix-based, in-place
8336:   ILU(0) preconditioner.

8338:   One can specify in-place ILU(0) factorization by calling
8339: .vb
8340:      PCType(pc,PCILU);
8341:      PCFactorSeUseInPlace(pc);
8342: .ve
8343:   or by using the options -pc_type ilu -pc_factor_in_place

8345:   In-place factorization ILU(0) can also be used as a local
8346:   solver for the blocks within the block Jacobi or additive Schwarz
8347:   methods (runtime option: -sub_pc_factor_in_place).  See Users-Manual: ch_pc
8348:   for details on setting local solver options.

8350:   Most users should employ the `KSP` interface for linear solvers
8351:   instead of working directly with matrix algebra routines such as this.
8352:   See, e.g., `KSPCreate()`.

8354: .seealso: [](ch_matrices), `Mat`, `PCFactorSetUseInPlace()`, `PCFactorGetUseInPlace()`
8355: @*/
8356: PetscErrorCode MatSetUnfactored(Mat mat)
8357: {
8358:   PetscFunctionBegin;
8361:   MatCheckPreallocated(mat, 1);
8362:   mat->factortype = MAT_FACTOR_NONE;
8363:   if (!mat->ops->setunfactored) PetscFunctionReturn(PETSC_SUCCESS);
8364:   PetscUseTypeMethod(mat, setunfactored);
8365:   PetscFunctionReturn(PETSC_SUCCESS);
8366: }

8368: /*MC
8369:     MatDenseGetArrayF90 - Accesses a matrix array from Fortran

8371:     Synopsis:
8372:     MatDenseGetArrayF90(Mat x,{Scalar, pointer :: xx_v(:,:)},integer ierr)

8374:     Not Collective

8376:     Input Parameter:
8377: .   x - matrix

8379:     Output Parameters:
8380: +   xx_v - the Fortran pointer to the array
8381: -   ierr - error code

8383:     Example of Usage:
8384: .vb
8385:       PetscScalar, pointer xx_v(:,:)
8386:       ....
8387:       call MatDenseGetArrayF90(x,xx_v,ierr)
8388:       a = xx_v(3)
8389:       call MatDenseRestoreArrayF90(x,xx_v,ierr)
8390: .ve

8392:     Level: advanced

8394: .seealso: [](ch_matrices), `Mat`, `MatDenseRestoreArrayF90()`, `MatDenseGetArray()`, `MatDenseRestoreArray()`, `MatSeqAIJGetArrayF90()`
8395: M*/

8397: /*MC
8398:     MatDenseRestoreArrayF90 - Restores a matrix array that has been
8399:     accessed with `MatDenseGetArrayF90()`.

8401:     Synopsis:
8402:     MatDenseRestoreArrayF90(Mat x,{Scalar, pointer :: xx_v(:,:)},integer ierr)

8404:     Not Collective

8406:     Input Parameters:
8407: +   x - matrix
8408: -   xx_v - the Fortran90 pointer to the array

8410:     Output Parameter:
8411: .   ierr - error code

8413:     Example of Usage:
8414: .vb
8415:        PetscScalar, pointer xx_v(:,:)
8416:        ....
8417:        call MatDenseGetArrayF90(x,xx_v,ierr)
8418:        a = xx_v(3)
8419:        call MatDenseRestoreArrayF90(x,xx_v,ierr)
8420: .ve

8422:     Level: advanced

8424: .seealso: [](ch_matrices), `Mat`, `MatDenseGetArrayF90()`, `MatDenseGetArray()`, `MatDenseRestoreArray()`, `MatSeqAIJRestoreArrayF90()`
8425: M*/

8427: /*MC
8428:     MatSeqAIJGetArrayF90 - Accesses a matrix array from Fortran.

8430:     Synopsis:
8431:     MatSeqAIJGetArrayF90(Mat x,{Scalar, pointer :: xx_v(:)},integer ierr)

8433:     Not Collective

8435:     Input Parameter:
8436: .   x - matrix

8438:     Output Parameters:
8439: +   xx_v - the Fortran pointer to the array
8440: -   ierr - error code

8442:     Example of Usage:
8443: .vb
8444:       PetscScalar, pointer xx_v(:)
8445:       ....
8446:       call MatSeqAIJGetArrayF90(x,xx_v,ierr)
8447:       a = xx_v(3)
8448:       call MatSeqAIJRestoreArrayF90(x,xx_v,ierr)
8449: .ve

8451:     Level: advanced

8453: .seealso: [](ch_matrices), `Mat`, `MatSeqAIJRestoreArrayF90()`, `MatSeqAIJGetArray()`, `MatSeqAIJRestoreArray()`, `MatDenseGetArrayF90()`
8454: M*/

8456: /*MC
8457:     MatSeqAIJRestoreArrayF90 - Restores a matrix array that has been
8458:     accessed with `MatSeqAIJGetArrayF90()`.

8460:     Synopsis:
8461:     MatSeqAIJRestoreArrayF90(Mat x,{Scalar, pointer :: xx_v(:)},integer ierr)

8463:     Not Collective

8465:     Input Parameters:
8466: +   x - matrix
8467: -   xx_v - the Fortran90 pointer to the array

8469:     Output Parameter:
8470: .   ierr - error code

8472:     Example of Usage:
8473: .vb
8474:        PetscScalar, pointer xx_v(:)
8475:        ....
8476:        call MatSeqAIJGetArrayF90(x,xx_v,ierr)
8477:        a = xx_v(3)
8478:        call MatSeqAIJRestoreArrayF90(x,xx_v,ierr)
8479: .ve

8481:     Level: advanced

8483: .seealso: [](ch_matrices), `Mat`, `MatSeqAIJGetArrayF90()`, `MatSeqAIJGetArray()`, `MatSeqAIJRestoreArray()`, `MatDenseRestoreArrayF90()`
8484: M*/

8486: /*@
8487:   MatCreateSubMatrix - Gets a single submatrix on the same number of processors
8488:   as the original matrix.

8490:   Collective

8492:   Input Parameters:
8493: + mat   - the original matrix
8494: . isrow - parallel `IS` containing the rows this processor should obtain
8495: . iscol - parallel `IS` containing all columns you wish to keep. Each process should list the columns that will be in IT's "diagonal part" in the new matrix.
8496: - cll   - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

8498:   Output Parameter:
8499: . newmat - the new submatrix, of the same type as the original matrix

8501:   Level: advanced

8503:   Notes:
8504:   The submatrix will be able to be multiplied with vectors using the same layout as `iscol`.

8506:   Some matrix types place restrictions on the row and column indices, such
8507:   as that they be sorted or that they be equal to each other. For `MATBAIJ` and `MATSBAIJ` matrices the indices must include all rows/columns of a block;
8508:   for example, if the block size is 3 one cannot select the 0 and 2 rows without selecting the 1 row.

8510:   The index sets may not have duplicate entries.

8512:   The first time this is called you should use a cll of `MAT_INITIAL_MATRIX`,
8513:   the `MatCreateSubMatrix()` routine will create the newmat for you. Any additional calls
8514:   to this routine with a mat of the same nonzero structure and with a call of `MAT_REUSE_MATRIX`
8515:   will reuse the matrix generated the first time.  You should call `MatDestroy()` on `newmat` when
8516:   you are finished using it.

8518:   The communicator of the newly obtained matrix is ALWAYS the same as the communicator of
8519:   the input matrix.

8521:   If `iscol` is `NULL` then all columns are obtained (not supported in Fortran).

8523:   If `isrow` and `iscol` have a nontrivial block-size, then the resulting matrix has this block-size as well. This feature
8524:   is used by `PCFIELDSPLIT` to allow easy nesting of its use.

8526:   Example usage:
8527:   Consider the following 8x8 matrix with 34 non-zero values, that is
8528:   assembled across 3 processors. Let's assume that proc0 owns 3 rows,
8529:   proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
8530:   as follows
8531: .vb
8532:             1  2  0  |  0  3  0  |  0  4
8533:     Proc0   0  5  6  |  7  0  0  |  8  0
8534:             9  0 10  | 11  0  0  | 12  0
8535:     -------------------------------------
8536:            13  0 14  | 15 16 17  |  0  0
8537:     Proc1   0 18  0  | 19 20 21  |  0  0
8538:             0  0  0  | 22 23  0  | 24  0
8539:     -------------------------------------
8540:     Proc2  25 26 27  |  0  0 28  | 29  0
8541:            30  0  0  | 31 32 33  |  0 34
8542: .ve

8544:   Suppose `isrow` = [0 1 | 4 | 6 7] and `iscol` = [1 2 | 3 4 5 | 6].  The resulting submatrix is

8546: .vb
8547:             2  0  |  0  3  0  |  0
8548:     Proc0   5  6  |  7  0  0  |  8
8549:     -------------------------------
8550:     Proc1  18  0  | 19 20 21  |  0
8551:     -------------------------------
8552:     Proc2  26 27  |  0  0 28  | 29
8553:             0  0  | 31 32 33  |  0
8554: .ve

8556: .seealso: [](ch_matrices), `Mat`, `MatCreateSubMatrices()`, `MatCreateSubMatricesMPI()`, `MatCreateSubMatrixVirtual()`, `MatSubMatrixVirtualUpdate()`
8557: @*/
8558: PetscErrorCode MatCreateSubMatrix(Mat mat, IS isrow, IS iscol, MatReuse cll, Mat *newmat)
8559: {
8560:   PetscMPIInt size;
8561:   Mat        *local;
8562:   IS          iscoltmp;
8563:   PetscBool   flg;

8565:   PetscFunctionBegin;
8569:   PetscAssertPointer(newmat, 5);
8572:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
8573:   PetscCheck(cll != MAT_IGNORE_MATRIX, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot use MAT_IGNORE_MATRIX");

8575:   MatCheckPreallocated(mat, 1);
8576:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size));

8578:   if (!iscol || isrow == iscol) {
8579:     PetscBool   stride;
8580:     PetscMPIInt grabentirematrix = 0, grab;
8581:     PetscCall(PetscObjectTypeCompare((PetscObject)isrow, ISSTRIDE, &stride));
8582:     if (stride) {
8583:       PetscInt first, step, n, rstart, rend;
8584:       PetscCall(ISStrideGetInfo(isrow, &first, &step));
8585:       if (step == 1) {
8586:         PetscCall(MatGetOwnershipRange(mat, &rstart, &rend));
8587:         if (rstart == first) {
8588:           PetscCall(ISGetLocalSize(isrow, &n));
8589:           if (n == rend - rstart) grabentirematrix = 1;
8590:         }
8591:       }
8592:     }
8593:     PetscCallMPI(MPIU_Allreduce(&grabentirematrix, &grab, 1, MPI_INT, MPI_MIN, PetscObjectComm((PetscObject)mat)));
8594:     if (grab) {
8595:       PetscCall(PetscInfo(mat, "Getting entire matrix as submatrix\n"));
8596:       if (cll == MAT_INITIAL_MATRIX) {
8597:         *newmat = mat;
8598:         PetscCall(PetscObjectReference((PetscObject)mat));
8599:       }
8600:       PetscFunctionReturn(PETSC_SUCCESS);
8601:     }
8602:   }

8604:   if (!iscol) {
8605:     PetscCall(ISCreateStride(PetscObjectComm((PetscObject)mat), mat->cmap->n, mat->cmap->rstart, 1, &iscoltmp));
8606:   } else {
8607:     iscoltmp = iscol;
8608:   }

8610:   /* if original matrix is on just one processor then use submatrix generated */
8611:   if (mat->ops->createsubmatrices && !mat->ops->createsubmatrix && size == 1 && cll == MAT_REUSE_MATRIX) {
8612:     PetscCall(MatCreateSubMatrices(mat, 1, &isrow, &iscoltmp, MAT_REUSE_MATRIX, &newmat));
8613:     goto setproperties;
8614:   } else if (mat->ops->createsubmatrices && !mat->ops->createsubmatrix && size == 1) {
8615:     PetscCall(MatCreateSubMatrices(mat, 1, &isrow, &iscoltmp, MAT_INITIAL_MATRIX, &local));
8616:     *newmat = *local;
8617:     PetscCall(PetscFree(local));
8618:     goto setproperties;
8619:   } else if (!mat->ops->createsubmatrix) {
8620:     /* Create a new matrix type that implements the operation using the full matrix */
8621:     PetscCall(PetscLogEventBegin(MAT_CreateSubMat, mat, 0, 0, 0));
8622:     switch (cll) {
8623:     case MAT_INITIAL_MATRIX:
8624:       PetscCall(MatCreateSubMatrixVirtual(mat, isrow, iscoltmp, newmat));
8625:       break;
8626:     case MAT_REUSE_MATRIX:
8627:       PetscCall(MatSubMatrixVirtualUpdate(*newmat, mat, isrow, iscoltmp));
8628:       break;
8629:     default:
8630:       SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Invalid MatReuse, must be either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX");
8631:     }
8632:     PetscCall(PetscLogEventEnd(MAT_CreateSubMat, mat, 0, 0, 0));
8633:     goto setproperties;
8634:   }

8636:   PetscCall(PetscLogEventBegin(MAT_CreateSubMat, mat, 0, 0, 0));
8637:   PetscUseTypeMethod(mat, createsubmatrix, isrow, iscoltmp, cll, newmat);
8638:   PetscCall(PetscLogEventEnd(MAT_CreateSubMat, mat, 0, 0, 0));

8640: setproperties:
8641:   if ((*newmat)->symmetric == PETSC_BOOL3_UNKNOWN && (*newmat)->structurally_symmetric == PETSC_BOOL3_UNKNOWN && (*newmat)->spd == PETSC_BOOL3_UNKNOWN && (*newmat)->hermitian == PETSC_BOOL3_UNKNOWN) {
8642:     PetscCall(ISEqualUnsorted(isrow, iscoltmp, &flg));
8643:     if (flg) PetscCall(MatPropagateSymmetryOptions(mat, *newmat));
8644:   }
8645:   if (!iscol) PetscCall(ISDestroy(&iscoltmp));
8646:   if (*newmat && cll == MAT_INITIAL_MATRIX) PetscCall(PetscObjectStateIncrease((PetscObject)*newmat));
8647:   PetscFunctionReturn(PETSC_SUCCESS);
8648: }

8650: /*@
8651:   MatPropagateSymmetryOptions - Propagates symmetry options set on a matrix to another matrix

8653:   Not Collective

8655:   Input Parameters:
8656: + A - the matrix we wish to propagate options from
8657: - B - the matrix we wish to propagate options to

8659:   Level: beginner

8661:   Note:
8662:   Propagates the options associated to `MAT_SYMMETRY_ETERNAL`, `MAT_STRUCTURALLY_SYMMETRIC`, `MAT_HERMITIAN`, `MAT_SPD`, `MAT_SYMMETRIC`, and `MAT_STRUCTURAL_SYMMETRY_ETERNAL`

8664: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatIsSymmetricKnown()`, `MatIsSPDKnown()`, `MatIsHermitianKnown()`, `MatIsStructurallySymmetricKnown()`
8665: @*/
8666: PetscErrorCode MatPropagateSymmetryOptions(Mat A, Mat B)
8667: {
8668:   PetscFunctionBegin;
8671:   B->symmetry_eternal            = A->symmetry_eternal;
8672:   B->structural_symmetry_eternal = A->structural_symmetry_eternal;
8673:   B->symmetric                   = A->symmetric;
8674:   B->structurally_symmetric      = A->structurally_symmetric;
8675:   B->spd                         = A->spd;
8676:   B->hermitian                   = A->hermitian;
8677:   PetscFunctionReturn(PETSC_SUCCESS);
8678: }

8680: /*@
8681:   MatStashSetInitialSize - sets the sizes of the matrix stash, that is
8682:   used during the assembly process to store values that belong to
8683:   other processors.

8685:   Not Collective

8687:   Input Parameters:
8688: + mat   - the matrix
8689: . size  - the initial size of the stash.
8690: - bsize - the initial size of the block-stash(if used).

8692:   Options Database Keys:
8693: + -matstash_initial_size <size> or <size0,size1,...sizep-1>            - set initial size
8694: - -matstash_block_initial_size <bsize>  or <bsize0,bsize1,...bsizep-1> - set initial block size

8696:   Level: intermediate

8698:   Notes:
8699:   The block-stash is used for values set with `MatSetValuesBlocked()` while
8700:   the stash is used for values set with `MatSetValues()`

8702:   Run with the option -info and look for output of the form
8703:   MatAssemblyBegin_MPIXXX:Stash has MM entries, uses nn mallocs.
8704:   to determine the appropriate value, MM, to use for size and
8705:   MatAssemblyBegin_MPIXXX:Block-Stash has BMM entries, uses nn mallocs.
8706:   to determine the value, BMM to use for bsize

8708: .seealso: [](ch_matrices), `MatAssemblyBegin()`, `MatAssemblyEnd()`, `Mat`, `MatStashGetInfo()`
8709: @*/
8710: PetscErrorCode MatStashSetInitialSize(Mat mat, PetscInt size, PetscInt bsize)
8711: {
8712:   PetscFunctionBegin;
8715:   PetscCall(MatStashSetInitialSize_Private(&mat->stash, size));
8716:   PetscCall(MatStashSetInitialSize_Private(&mat->bstash, bsize));
8717:   PetscFunctionReturn(PETSC_SUCCESS);
8718: }

8720: /*@
8721:   MatInterpolateAdd - $w = y + A*x$ or $A^T*x$ depending on the shape of
8722:   the matrix

8724:   Neighbor-wise Collective

8726:   Input Parameters:
8727: + A - the matrix
8728: . x - the vector to be multiplied by the interpolation operator
8729: - y - the vector to be added to the result

8731:   Output Parameter:
8732: . w - the resulting vector

8734:   Level: intermediate

8736:   Notes:
8737:   `w` may be the same vector as `y`.

8739:   This allows one to use either the restriction or interpolation (its transpose)
8740:   matrix to do the interpolation

8742: .seealso: [](ch_matrices), `Mat`, `MatMultAdd()`, `MatMultTransposeAdd()`, `MatRestrict()`, `PCMG`
8743: @*/
8744: PetscErrorCode MatInterpolateAdd(Mat A, Vec x, Vec y, Vec w)
8745: {
8746:   PetscInt M, N, Ny;

8748:   PetscFunctionBegin;
8753:   PetscCall(MatGetSize(A, &M, &N));
8754:   PetscCall(VecGetSize(y, &Ny));
8755:   if (M == Ny) {
8756:     PetscCall(MatMultAdd(A, x, y, w));
8757:   } else {
8758:     PetscCall(MatMultTransposeAdd(A, x, y, w));
8759:   }
8760:   PetscFunctionReturn(PETSC_SUCCESS);
8761: }

8763: /*@
8764:   MatInterpolate - $y = A*x$ or $A^T*x$ depending on the shape of
8765:   the matrix

8767:   Neighbor-wise Collective

8769:   Input Parameters:
8770: + A - the matrix
8771: - x - the vector to be interpolated

8773:   Output Parameter:
8774: . y - the resulting vector

8776:   Level: intermediate

8778:   Note:
8779:   This allows one to use either the restriction or interpolation (its transpose)
8780:   matrix to do the interpolation

8782: .seealso: [](ch_matrices), `Mat`, `MatMultAdd()`, `MatMultTransposeAdd()`, `MatRestrict()`, `PCMG`
8783: @*/
8784: PetscErrorCode MatInterpolate(Mat A, Vec x, Vec y)
8785: {
8786:   PetscInt M, N, Ny;

8788:   PetscFunctionBegin;
8792:   PetscCall(MatGetSize(A, &M, &N));
8793:   PetscCall(VecGetSize(y, &Ny));
8794:   if (M == Ny) {
8795:     PetscCall(MatMult(A, x, y));
8796:   } else {
8797:     PetscCall(MatMultTranspose(A, x, y));
8798:   }
8799:   PetscFunctionReturn(PETSC_SUCCESS);
8800: }

8802: /*@
8803:   MatRestrict - $y = A*x$ or $A^T*x$

8805:   Neighbor-wise Collective

8807:   Input Parameters:
8808: + A - the matrix
8809: - x - the vector to be restricted

8811:   Output Parameter:
8812: . y - the resulting vector

8814:   Level: intermediate

8816:   Note:
8817:   This allows one to use either the restriction or interpolation (its transpose)
8818:   matrix to do the restriction

8820: .seealso: [](ch_matrices), `Mat`, `MatMultAdd()`, `MatMultTransposeAdd()`, `MatInterpolate()`, `PCMG`
8821: @*/
8822: PetscErrorCode MatRestrict(Mat A, Vec x, Vec y)
8823: {
8824:   PetscInt M, N, Nx;

8826:   PetscFunctionBegin;
8830:   PetscCall(MatGetSize(A, &M, &N));
8831:   PetscCall(VecGetSize(x, &Nx));
8832:   if (M == Nx) {
8833:     PetscCall(MatMultTranspose(A, x, y));
8834:   } else {
8835:     PetscCall(MatMult(A, x, y));
8836:   }
8837:   PetscFunctionReturn(PETSC_SUCCESS);
8838: }

8840: /*@
8841:   MatMatInterpolateAdd - $Y = W + A*X$ or $W + A^T*X$ depending on the shape of `A`

8843:   Neighbor-wise Collective

8845:   Input Parameters:
8846: + A - the matrix
8847: . x - the input dense matrix to be multiplied
8848: - w - the input dense matrix to be added to the result

8850:   Output Parameter:
8851: . y - the output dense matrix

8853:   Level: intermediate

8855:   Note:
8856:   This allows one to use either the restriction or interpolation (its transpose)
8857:   matrix to do the interpolation. `y` matrix can be reused if already created with the proper sizes,
8858:   otherwise it will be recreated. `y` must be initialized to `NULL` if not supplied.

8860: .seealso: [](ch_matrices), `Mat`, `MatInterpolateAdd()`, `MatMatInterpolate()`, `MatMatRestrict()`, `PCMG`
8861: @*/
8862: PetscErrorCode MatMatInterpolateAdd(Mat A, Mat x, Mat w, Mat *y)
8863: {
8864:   PetscInt  M, N, Mx, Nx, Mo, My = 0, Ny = 0;
8865:   PetscBool trans = PETSC_TRUE;
8866:   MatReuse  reuse = MAT_INITIAL_MATRIX;

8868:   PetscFunctionBegin;
8874:   PetscCall(MatGetSize(A, &M, &N));
8875:   PetscCall(MatGetSize(x, &Mx, &Nx));
8876:   if (N == Mx) trans = PETSC_FALSE;
8877:   else PetscCheck(M == Mx, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Size mismatch: A %" PetscInt_FMT "x%" PetscInt_FMT ", X %" PetscInt_FMT "x%" PetscInt_FMT, M, N, Mx, Nx);
8878:   Mo = trans ? N : M;
8879:   if (*y) {
8880:     PetscCall(MatGetSize(*y, &My, &Ny));
8881:     if (Mo == My && Nx == Ny) {
8882:       reuse = MAT_REUSE_MATRIX;
8883:     } else {
8884:       PetscCheck(w || *y != w, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot reuse y and w, size mismatch: A %" PetscInt_FMT "x%" PetscInt_FMT ", X %" PetscInt_FMT "x%" PetscInt_FMT ", Y %" PetscInt_FMT "x%" PetscInt_FMT, M, N, Mx, Nx, My, Ny);
8885:       PetscCall(MatDestroy(y));
8886:     }
8887:   }

8889:   if (w && *y == w) { /* this is to minimize changes in PCMG */
8890:     PetscBool flg;

8892:     PetscCall(PetscObjectQuery((PetscObject)*y, "__MatMatIntAdd_w", (PetscObject *)&w));
8893:     if (w) {
8894:       PetscInt My, Ny, Mw, Nw;

8896:       PetscCall(PetscObjectTypeCompare((PetscObject)*y, ((PetscObject)w)->type_name, &flg));
8897:       PetscCall(MatGetSize(*y, &My, &Ny));
8898:       PetscCall(MatGetSize(w, &Mw, &Nw));
8899:       if (!flg || My != Mw || Ny != Nw) w = NULL;
8900:     }
8901:     if (!w) {
8902:       PetscCall(MatDuplicate(*y, MAT_COPY_VALUES, &w));
8903:       PetscCall(PetscObjectCompose((PetscObject)*y, "__MatMatIntAdd_w", (PetscObject)w));
8904:       PetscCall(PetscObjectDereference((PetscObject)w));
8905:     } else {
8906:       PetscCall(MatCopy(*y, w, UNKNOWN_NONZERO_PATTERN));
8907:     }
8908:   }
8909:   if (!trans) {
8910:     PetscCall(MatMatMult(A, x, reuse, PETSC_DETERMINE, y));
8911:   } else {
8912:     PetscCall(MatTransposeMatMult(A, x, reuse, PETSC_DETERMINE, y));
8913:   }
8914:   if (w) PetscCall(MatAXPY(*y, 1.0, w, UNKNOWN_NONZERO_PATTERN));
8915:   PetscFunctionReturn(PETSC_SUCCESS);
8916: }

8918: /*@
8919:   MatMatInterpolate - $Y = A*X$ or $A^T*X$ depending on the shape of `A`

8921:   Neighbor-wise Collective

8923:   Input Parameters:
8924: + A - the matrix
8925: - x - the input dense matrix

8927:   Output Parameter:
8928: . y - the output dense matrix

8930:   Level: intermediate

8932:   Note:
8933:   This allows one to use either the restriction or interpolation (its transpose)
8934:   matrix to do the interpolation. `y` matrix can be reused if already created with the proper sizes,
8935:   otherwise it will be recreated. `y` must be initialized to `NULL` if not supplied.

8937: .seealso: [](ch_matrices), `Mat`, `MatInterpolate()`, `MatRestrict()`, `MatMatRestrict()`, `PCMG`
8938: @*/
8939: PetscErrorCode MatMatInterpolate(Mat A, Mat x, Mat *y)
8940: {
8941:   PetscFunctionBegin;
8942:   PetscCall(MatMatInterpolateAdd(A, x, NULL, y));
8943:   PetscFunctionReturn(PETSC_SUCCESS);
8944: }

8946: /*@
8947:   MatMatRestrict - $Y = A*X$ or $A^T*X$ depending on the shape of `A`

8949:   Neighbor-wise Collective

8951:   Input Parameters:
8952: + A - the matrix
8953: - x - the input dense matrix

8955:   Output Parameter:
8956: . y - the output dense matrix

8958:   Level: intermediate

8960:   Note:
8961:   This allows one to use either the restriction or interpolation (its transpose)
8962:   matrix to do the restriction. `y` matrix can be reused if already created with the proper sizes,
8963:   otherwise it will be recreated. `y` must be initialized to `NULL` if not supplied.

8965: .seealso: [](ch_matrices), `Mat`, `MatRestrict()`, `MatInterpolate()`, `MatMatInterpolate()`, `PCMG`
8966: @*/
8967: PetscErrorCode MatMatRestrict(Mat A, Mat x, Mat *y)
8968: {
8969:   PetscFunctionBegin;
8970:   PetscCall(MatMatInterpolateAdd(A, x, NULL, y));
8971:   PetscFunctionReturn(PETSC_SUCCESS);
8972: }

8974: /*@
8975:   MatGetNullSpace - retrieves the null space of a matrix.

8977:   Logically Collective

8979:   Input Parameters:
8980: + mat    - the matrix
8981: - nullsp - the null space object

8983:   Level: developer

8985: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatSetNullSpace()`, `MatNullSpace`
8986: @*/
8987: PetscErrorCode MatGetNullSpace(Mat mat, MatNullSpace *nullsp)
8988: {
8989:   PetscFunctionBegin;
8991:   PetscAssertPointer(nullsp, 2);
8992:   *nullsp = (mat->symmetric == PETSC_BOOL3_TRUE && !mat->nullsp) ? mat->transnullsp : mat->nullsp;
8993:   PetscFunctionReturn(PETSC_SUCCESS);
8994: }

8996: /*@C
8997:   MatGetNullSpaces - gets the null spaces, transpose null spaces, and near null spaces from an array of matrices

8999:   Logically Collective

9001:   Input Parameters:
9002: + n   - the number of matrices
9003: - mat - the array of matrices

9005:   Output Parameters:
9006: . nullsp - an array of null spaces, `NULL` for each matrix that does not have a null space, length 3 * `n`

9008:   Level: developer

9010:   Note:
9011:   Call `MatRestoreNullspaces()` to provide these to another array of matrices

9013: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatSetTransposeNullSpace()`, `MatGetTransposeNullSpace()`,
9014:           `MatNullSpaceRemove()`, `MatRestoreNullSpaces()`
9015: @*/
9016: PetscErrorCode MatGetNullSpaces(PetscInt n, Mat mat[], MatNullSpace *nullsp[])
9017: {
9018:   PetscFunctionBegin;
9019:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of matrices %" PetscInt_FMT " must be non-negative", n);
9020:   PetscAssertPointer(mat, 2);
9021:   PetscAssertPointer(nullsp, 3);

9023:   PetscCall(PetscCalloc1(3 * n, nullsp));
9024:   for (PetscInt i = 0; i < n; i++) {
9026:     (*nullsp)[i] = mat[i]->nullsp;
9027:     PetscCall(PetscObjectReference((PetscObject)(*nullsp)[i]));
9028:     (*nullsp)[n + i] = mat[i]->nearnullsp;
9029:     PetscCall(PetscObjectReference((PetscObject)(*nullsp)[n + i]));
9030:     (*nullsp)[2 * n + i] = mat[i]->transnullsp;
9031:     PetscCall(PetscObjectReference((PetscObject)(*nullsp)[2 * n + i]));
9032:   }
9033:   PetscFunctionReturn(PETSC_SUCCESS);
9034: }

9036: /*@C
9037:   MatRestoreNullSpaces - sets the null spaces, transpose null spaces, and near null spaces obtained with `MatGetNullSpaces()` for an array of matrices

9039:   Logically Collective

9041:   Input Parameters:
9042: + n      - the number of matrices
9043: . mat    - the array of matrices
9044: - nullsp - an array of null spaces

9046:   Level: developer

9048:   Note:
9049:   Call `MatGetNullSpaces()` to create `nullsp`

9051: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatSetTransposeNullSpace()`, `MatGetTransposeNullSpace()`,
9052:           `MatNullSpaceRemove()`, `MatGetNullSpaces()`
9053: @*/
9054: PetscErrorCode MatRestoreNullSpaces(PetscInt n, Mat mat[], MatNullSpace *nullsp[])
9055: {
9056:   PetscFunctionBegin;
9057:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of matrices %" PetscInt_FMT " must be non-negative", n);
9058:   PetscAssertPointer(mat, 2);
9059:   PetscAssertPointer(nullsp, 3);
9060:   PetscAssertPointer(*nullsp, 3);

9062:   for (PetscInt i = 0; i < n; i++) {
9064:     PetscCall(MatSetNullSpace(mat[i], (*nullsp)[i]));
9065:     PetscCall(PetscObjectDereference((PetscObject)(*nullsp)[i]));
9066:     PetscCall(MatSetNearNullSpace(mat[i], (*nullsp)[n + i]));
9067:     PetscCall(PetscObjectDereference((PetscObject)(*nullsp)[n + i]));
9068:     PetscCall(MatSetTransposeNullSpace(mat[i], (*nullsp)[2 * n + i]));
9069:     PetscCall(PetscObjectDereference((PetscObject)(*nullsp)[2 * n + i]));
9070:   }
9071:   PetscCall(PetscFree(*nullsp));
9072:   PetscFunctionReturn(PETSC_SUCCESS);
9073: }

9075: /*@
9076:   MatSetNullSpace - attaches a null space to a matrix.

9078:   Logically Collective

9080:   Input Parameters:
9081: + mat    - the matrix
9082: - nullsp - the null space object

9084:   Level: advanced

9086:   Notes:
9087:   This null space is used by the `KSP` linear solvers to solve singular systems.

9089:   Overwrites any previous null space that may have been attached. You can remove the null space from the matrix object by calling this routine with an nullsp of `NULL`

9091:   For inconsistent singular systems (linear systems where the right-hand side is not in the range of the operator) the `KSP` residuals will not converge
9092:   to zero but the linear system will still be solved in a least squares sense.

9094:   The fundamental theorem of linear algebra (Gilbert Strang, Introduction to Applied Mathematics, page 72) states that
9095:   the domain of a matrix A (from $R^n$ to $R^m$ (m rows, n columns) $R^n$ = the direct sum of the null space of A, n(A), + the range of $A^T$, $R(A^T)$.
9096:   Similarly $R^m$ = direct sum n($A^T$) + R(A).  Hence the linear system $A x = b$ has a solution only if b in R(A) (or correspondingly b is orthogonal to
9097:   n($A^T$)) and if x is a solution then x + alpha n(A) is a solution for any alpha. The minimum norm solution is orthogonal to n(A). For problems without a solution
9098:   the solution that minimizes the norm of the residual (the least squares solution) can be obtained by solving A x = \hat{b} where \hat{b} is b orthogonalized to the n($A^T$).
9099:   This  \hat{b} can be obtained by calling `MatNullSpaceRemove()` with the null space of the transpose of the matrix.

9101:   If the matrix is known to be symmetric because it is an `MATSBAIJ` matrix or one as called
9102:   `MatSetOption`(mat,`MAT_SYMMETRIC` or possibly `MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`); this
9103:   routine also automatically calls `MatSetTransposeNullSpace()`.

9105:   The user should call `MatNullSpaceDestroy()`.

9107: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatSetTransposeNullSpace()`, `MatGetTransposeNullSpace()`, `MatNullSpaceRemove()`,
9108:           `KSPSetPCSide()`
9109: @*/
9110: PetscErrorCode MatSetNullSpace(Mat mat, MatNullSpace nullsp)
9111: {
9112:   PetscFunctionBegin;
9115:   if (nullsp) PetscCall(PetscObjectReference((PetscObject)nullsp));
9116:   PetscCall(MatNullSpaceDestroy(&mat->nullsp));
9117:   mat->nullsp = nullsp;
9118:   if (mat->symmetric == PETSC_BOOL3_TRUE) PetscCall(MatSetTransposeNullSpace(mat, nullsp));
9119:   PetscFunctionReturn(PETSC_SUCCESS);
9120: }

9122: /*@
9123:   MatGetTransposeNullSpace - retrieves the null space of the transpose of a matrix.

9125:   Logically Collective

9127:   Input Parameters:
9128: + mat    - the matrix
9129: - nullsp - the null space object

9131:   Level: developer

9133: .seealso: [](ch_matrices), `Mat`, `MatNullSpace`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatSetTransposeNullSpace()`, `MatSetNullSpace()`, `MatGetNullSpace()`
9134: @*/
9135: PetscErrorCode MatGetTransposeNullSpace(Mat mat, MatNullSpace *nullsp)
9136: {
9137:   PetscFunctionBegin;
9140:   PetscAssertPointer(nullsp, 2);
9141:   *nullsp = (mat->symmetric == PETSC_BOOL3_TRUE && !mat->transnullsp) ? mat->nullsp : mat->transnullsp;
9142:   PetscFunctionReturn(PETSC_SUCCESS);
9143: }

9145: /*@
9146:   MatSetTransposeNullSpace - attaches the null space of a transpose of a matrix to the matrix

9148:   Logically Collective

9150:   Input Parameters:
9151: + mat    - the matrix
9152: - nullsp - the null space object

9154:   Level: advanced

9156:   Notes:
9157:   This allows solving singular linear systems defined by the transpose of the matrix using `KSP` solvers with left preconditioning.

9159:   See `MatSetNullSpace()`

9161: .seealso: [](ch_matrices), `Mat`, `MatNullSpace`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatSetNullSpace()`, `MatGetTransposeNullSpace()`, `MatNullSpaceRemove()`, `KSPSetPCSide()`
9162: @*/
9163: PetscErrorCode MatSetTransposeNullSpace(Mat mat, MatNullSpace nullsp)
9164: {
9165:   PetscFunctionBegin;
9168:   if (nullsp) PetscCall(PetscObjectReference((PetscObject)nullsp));
9169:   PetscCall(MatNullSpaceDestroy(&mat->transnullsp));
9170:   mat->transnullsp = nullsp;
9171:   PetscFunctionReturn(PETSC_SUCCESS);
9172: }

9174: /*@
9175:   MatSetNearNullSpace - attaches a null space to a matrix, which is often the null space (rigid body modes) of the operator without boundary conditions
9176:   This null space will be used to provide near null space vectors to a multigrid preconditioner built from this matrix.

9178:   Logically Collective

9180:   Input Parameters:
9181: + mat    - the matrix
9182: - nullsp - the null space object

9184:   Level: advanced

9186:   Notes:
9187:   Overwrites any previous near null space that may have been attached

9189:   You can remove the null space by calling this routine with an `nullsp` of `NULL`

9191: .seealso: [](ch_matrices), `Mat`, `MatNullSpace`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNullSpace()`, `MatNullSpaceCreateRigidBody()`, `MatGetNearNullSpace()`
9192: @*/
9193: PetscErrorCode MatSetNearNullSpace(Mat mat, MatNullSpace nullsp)
9194: {
9195:   PetscFunctionBegin;
9199:   MatCheckPreallocated(mat, 1);
9200:   if (nullsp) PetscCall(PetscObjectReference((PetscObject)nullsp));
9201:   PetscCall(MatNullSpaceDestroy(&mat->nearnullsp));
9202:   mat->nearnullsp = nullsp;
9203:   PetscFunctionReturn(PETSC_SUCCESS);
9204: }

9206: /*@
9207:   MatGetNearNullSpace - Get null space attached with `MatSetNearNullSpace()`

9209:   Not Collective

9211:   Input Parameter:
9212: . mat - the matrix

9214:   Output Parameter:
9215: . nullsp - the null space object, `NULL` if not set

9217:   Level: advanced

9219: .seealso: [](ch_matrices), `Mat`, `MatNullSpace`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatNullSpaceCreate()`
9220: @*/
9221: PetscErrorCode MatGetNearNullSpace(Mat mat, MatNullSpace *nullsp)
9222: {
9223:   PetscFunctionBegin;
9226:   PetscAssertPointer(nullsp, 2);
9227:   MatCheckPreallocated(mat, 1);
9228:   *nullsp = mat->nearnullsp;
9229:   PetscFunctionReturn(PETSC_SUCCESS);
9230: }

9232: /*@
9233:   MatICCFactor - Performs in-place incomplete Cholesky factorization of matrix.

9235:   Collective

9237:   Input Parameters:
9238: + mat  - the matrix
9239: . row  - row/column permutation
9240: - info - information on desired factorization process

9242:   Level: developer

9244:   Notes:
9245:   Probably really in-place only when level of fill is zero, otherwise allocates
9246:   new space to store factored matrix and deletes previous memory.

9248:   Most users should employ the `KSP` interface for linear solvers
9249:   instead of working directly with matrix algebra routines such as this.
9250:   See, e.g., `KSPCreate()`.

9252:   Developer Note:
9253:   The Fortran interface is not autogenerated as the
9254:   interface definition cannot be generated correctly [due to `MatFactorInfo`]

9256: .seealso: [](ch_matrices), `Mat`, `MatFactorInfo`, `MatGetFactor()`, `MatICCFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`
9257: @*/
9258: PetscErrorCode MatICCFactor(Mat mat, IS row, const MatFactorInfo *info)
9259: {
9260:   PetscFunctionBegin;
9264:   PetscAssertPointer(info, 3);
9265:   PetscCheck(mat->rmap->N == mat->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "matrix must be square");
9266:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
9267:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
9268:   MatCheckPreallocated(mat, 1);
9269:   PetscUseTypeMethod(mat, iccfactor, row, info);
9270:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
9271:   PetscFunctionReturn(PETSC_SUCCESS);
9272: }

9274: /*@
9275:   MatDiagonalScaleLocal - Scales columns of a matrix given the scaling values including the
9276:   ghosted ones.

9278:   Not Collective

9280:   Input Parameters:
9281: + mat  - the matrix
9282: - diag - the diagonal values, including ghost ones

9284:   Level: developer

9286:   Notes:
9287:   Works only for `MATMPIAIJ` and `MATMPIBAIJ` matrices

9289:   This allows one to avoid during communication to perform the scaling that must be done with `MatDiagonalScale()`

9291: .seealso: [](ch_matrices), `Mat`, `MatDiagonalScale()`
9292: @*/
9293: PetscErrorCode MatDiagonalScaleLocal(Mat mat, Vec diag)
9294: {
9295:   PetscMPIInt size;

9297:   PetscFunctionBegin;

9302:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Matrix must be already assembled");
9303:   PetscCall(PetscLogEventBegin(MAT_Scale, mat, 0, 0, 0));
9304:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size));
9305:   if (size == 1) {
9306:     PetscInt n, m;
9307:     PetscCall(VecGetSize(diag, &n));
9308:     PetscCall(MatGetSize(mat, NULL, &m));
9309:     PetscCheck(m == n, PETSC_COMM_SELF, PETSC_ERR_SUP, "Only supported for sequential matrices when no ghost points/periodic conditions");
9310:     PetscCall(MatDiagonalScale(mat, NULL, diag));
9311:   } else {
9312:     PetscUseMethod(mat, "MatDiagonalScaleLocal_C", (Mat, Vec), (mat, diag));
9313:   }
9314:   PetscCall(PetscLogEventEnd(MAT_Scale, mat, 0, 0, 0));
9315:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
9316:   PetscFunctionReturn(PETSC_SUCCESS);
9317: }

9319: /*@
9320:   MatGetInertia - Gets the inertia from a factored matrix

9322:   Collective

9324:   Input Parameter:
9325: . mat - the matrix

9327:   Output Parameters:
9328: + nneg  - number of negative eigenvalues
9329: . nzero - number of zero eigenvalues
9330: - npos  - number of positive eigenvalues

9332:   Level: advanced

9334:   Note:
9335:   Matrix must have been factored by `MatCholeskyFactor()`

9337: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatCholeskyFactor()`
9338: @*/
9339: PetscErrorCode MatGetInertia(Mat mat, PetscInt *nneg, PetscInt *nzero, PetscInt *npos)
9340: {
9341:   PetscFunctionBegin;
9344:   PetscCheck(mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Unfactored matrix");
9345:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Numeric factor mat is not assembled");
9346:   PetscUseTypeMethod(mat, getinertia, nneg, nzero, npos);
9347:   PetscFunctionReturn(PETSC_SUCCESS);
9348: }

9350: /*@C
9351:   MatSolves - Solves $A x = b$, given a factored matrix, for a collection of vectors

9353:   Neighbor-wise Collective

9355:   Input Parameters:
9356: + mat - the factored matrix obtained with `MatGetFactor()`
9357: - b   - the right-hand-side vectors

9359:   Output Parameter:
9360: . x - the result vectors

9362:   Level: developer

9364:   Note:
9365:   The vectors `b` and `x` cannot be the same.  I.e., one cannot
9366:   call `MatSolves`(A,x,x).

9368: .seealso: [](ch_matrices), `Mat`, `Vecs`, `MatSolveAdd()`, `MatSolveTranspose()`, `MatSolveTransposeAdd()`, `MatSolve()`
9369: @*/
9370: PetscErrorCode MatSolves(Mat mat, Vecs b, Vecs x)
9371: {
9372:   PetscFunctionBegin;
9375:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
9376:   PetscCheck(mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Unfactored matrix");
9377:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);

9379:   MatCheckPreallocated(mat, 1);
9380:   PetscCall(PetscLogEventBegin(MAT_Solves, mat, 0, 0, 0));
9381:   PetscUseTypeMethod(mat, solves, b, x);
9382:   PetscCall(PetscLogEventEnd(MAT_Solves, mat, 0, 0, 0));
9383:   PetscFunctionReturn(PETSC_SUCCESS);
9384: }

9386: /*@
9387:   MatIsSymmetric - Test whether a matrix is symmetric

9389:   Collective

9391:   Input Parameters:
9392: + A   - the matrix to test
9393: - tol - difference between value and its transpose less than this amount counts as equal (use 0.0 for exact transpose)

9395:   Output Parameter:
9396: . flg - the result

9398:   Level: intermediate

9400:   Notes:
9401:   For real numbers `MatIsSymmetric()` and `MatIsHermitian()` return identical results

9403:   If the matrix does not yet know if it is symmetric or not this can be an expensive operation, also available `MatIsSymmetricKnown()`

9405:   One can declare that a matrix is symmetric with `MatSetOption`(mat,`MAT_SYMMETRIC`,`PETSC_TRUE`) and if it is known to remain symmetric
9406:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`)

9408: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetricKnown()`,
9409:           `MAT_SYMMETRIC`, `MAT_SYMMETRY_ETERNAL`
9410: @*/
9411: PetscErrorCode MatIsSymmetric(Mat A, PetscReal tol, PetscBool *flg)
9412: {
9413:   PetscFunctionBegin;
9415:   PetscAssertPointer(flg, 3);
9416:   if (A->symmetric != PETSC_BOOL3_UNKNOWN && !tol) *flg = PetscBool3ToBool(A->symmetric);
9417:   else {
9418:     if (A->ops->issymmetric) PetscUseTypeMethod(A, issymmetric, tol, flg);
9419:     else PetscCall(MatIsTranspose(A, A, tol, flg));
9420:     if (!tol) PetscCall(MatSetOption(A, MAT_SYMMETRIC, *flg));
9421:   }
9422:   PetscFunctionReturn(PETSC_SUCCESS);
9423: }

9425: /*@
9426:   MatIsHermitian - Test whether a matrix is Hermitian

9428:   Collective

9430:   Input Parameters:
9431: + A   - the matrix to test
9432: - tol - difference between value and its transpose less than this amount counts as equal (use 0.0 for exact Hermitian)

9434:   Output Parameter:
9435: . flg - the result

9437:   Level: intermediate

9439:   Notes:
9440:   For real numbers `MatIsSymmetric()` and `MatIsHermitian()` return identical results

9442:   If the matrix does not yet know if it is Hermitian or not this can be an expensive operation, also available `MatIsHermitianKnown()`

9444:   One can declare that a matrix is Hermitian with `MatSetOption`(mat,`MAT_HERMITIAN`,`PETSC_TRUE`) and if it is known to remain Hermitian
9445:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SYMEMTRY_ETERNAL`,`PETSC_TRUE`)

9447: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitianKnown()`, `MatIsStructurallySymmetric()`, `MatSetOption()`,
9448:           `MatIsSymmetricKnown()`, `MatIsSymmetric()`, `MAT_HERMITIAN`, `MAT_SYMMETRY_ETERNAL`
9449: @*/
9450: PetscErrorCode MatIsHermitian(Mat A, PetscReal tol, PetscBool *flg)
9451: {
9452:   PetscFunctionBegin;
9454:   PetscAssertPointer(flg, 3);
9455:   if (A->hermitian != PETSC_BOOL3_UNKNOWN && !tol) *flg = PetscBool3ToBool(A->hermitian);
9456:   else {
9457:     if (A->ops->ishermitian) PetscUseTypeMethod(A, ishermitian, tol, flg);
9458:     else PetscCall(MatIsHermitianTranspose(A, A, tol, flg));
9459:     if (!tol) PetscCall(MatSetOption(A, MAT_HERMITIAN, *flg));
9460:   }
9461:   PetscFunctionReturn(PETSC_SUCCESS);
9462: }

9464: /*@
9465:   MatIsSymmetricKnown - Checks if a matrix knows if it is symmetric or not and its symmetric state

9467:   Not Collective

9469:   Input Parameter:
9470: . A - the matrix to check

9472:   Output Parameters:
9473: + set - `PETSC_TRUE` if the matrix knows its symmetry state (this tells you if the next flag is valid)
9474: - flg - the result (only valid if set is `PETSC_TRUE`)

9476:   Level: advanced

9478:   Notes:
9479:   Does not check the matrix values directly, so this may return unknown (set = `PETSC_FALSE`). Use `MatIsSymmetric()`
9480:   if you want it explicitly checked

9482:   One can declare that a matrix is symmetric with `MatSetOption`(mat,`MAT_SYMMETRIC`,`PETSC_TRUE`) and if it is known to remain symmetric
9483:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`)

9485: .seealso: [](ch_matrices), `Mat`, `MAT_SYMMETRY_ETERNAL`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetric()`, `MatIsHermitianKnown()`
9486: @*/
9487: PetscErrorCode MatIsSymmetricKnown(Mat A, PetscBool *set, PetscBool *flg)
9488: {
9489:   PetscFunctionBegin;
9491:   PetscAssertPointer(set, 2);
9492:   PetscAssertPointer(flg, 3);
9493:   if (A->symmetric != PETSC_BOOL3_UNKNOWN) {
9494:     *set = PETSC_TRUE;
9495:     *flg = PetscBool3ToBool(A->symmetric);
9496:   } else {
9497:     *set = PETSC_FALSE;
9498:   }
9499:   PetscFunctionReturn(PETSC_SUCCESS);
9500: }

9502: /*@
9503:   MatIsSPDKnown - Checks if a matrix knows if it is symmetric positive definite or not and its symmetric positive definite state

9505:   Not Collective

9507:   Input Parameter:
9508: . A - the matrix to check

9510:   Output Parameters:
9511: + set - `PETSC_TRUE` if the matrix knows its symmetric positive definite state (this tells you if the next flag is valid)
9512: - flg - the result (only valid if set is `PETSC_TRUE`)

9514:   Level: advanced

9516:   Notes:
9517:   Does not check the matrix values directly, so this may return unknown (set = `PETSC_FALSE`).

9519:   One can declare that a matrix is SPD with `MatSetOption`(mat,`MAT_SPD`,`PETSC_TRUE`) and if it is known to remain SPD
9520:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SPD_ETERNAL`,`PETSC_TRUE`)

9522: .seealso: [](ch_matrices), `Mat`, `MAT_SPD_ETERNAL`, `MAT_SPD`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetric()`, `MatIsHermitianKnown()`
9523: @*/
9524: PetscErrorCode MatIsSPDKnown(Mat A, PetscBool *set, PetscBool *flg)
9525: {
9526:   PetscFunctionBegin;
9528:   PetscAssertPointer(set, 2);
9529:   PetscAssertPointer(flg, 3);
9530:   if (A->spd != PETSC_BOOL3_UNKNOWN) {
9531:     *set = PETSC_TRUE;
9532:     *flg = PetscBool3ToBool(A->spd);
9533:   } else {
9534:     *set = PETSC_FALSE;
9535:   }
9536:   PetscFunctionReturn(PETSC_SUCCESS);
9537: }

9539: /*@
9540:   MatIsHermitianKnown - Checks if a matrix knows if it is Hermitian or not and its Hermitian state

9542:   Not Collective

9544:   Input Parameter:
9545: . A - the matrix to check

9547:   Output Parameters:
9548: + set - `PETSC_TRUE` if the matrix knows its Hermitian state (this tells you if the next flag is valid)
9549: - flg - the result (only valid if set is `PETSC_TRUE`)

9551:   Level: advanced

9553:   Notes:
9554:   Does not check the matrix values directly, so this may return unknown (set = `PETSC_FALSE`). Use `MatIsHermitian()`
9555:   if you want it explicitly checked

9557:   One can declare that a matrix is Hermitian with `MatSetOption`(mat,`MAT_HERMITIAN`,`PETSC_TRUE`) and if it is known to remain Hermitian
9558:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`)

9560: .seealso: [](ch_matrices), `Mat`, `MAT_SYMMETRY_ETERNAL`, `MAT_HERMITIAN`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetric()`
9561: @*/
9562: PetscErrorCode MatIsHermitianKnown(Mat A, PetscBool *set, PetscBool *flg)
9563: {
9564:   PetscFunctionBegin;
9566:   PetscAssertPointer(set, 2);
9567:   PetscAssertPointer(flg, 3);
9568:   if (A->hermitian != PETSC_BOOL3_UNKNOWN) {
9569:     *set = PETSC_TRUE;
9570:     *flg = PetscBool3ToBool(A->hermitian);
9571:   } else {
9572:     *set = PETSC_FALSE;
9573:   }
9574:   PetscFunctionReturn(PETSC_SUCCESS);
9575: }

9577: /*@
9578:   MatIsStructurallySymmetric - Test whether a matrix is structurally symmetric

9580:   Collective

9582:   Input Parameter:
9583: . A - the matrix to test

9585:   Output Parameter:
9586: . flg - the result

9588:   Level: intermediate

9590:   Notes:
9591:   If the matrix does yet know it is structurally symmetric this can be an expensive operation, also available `MatIsStructurallySymmetricKnown()`

9593:   One can declare that a matrix is structurally symmetric with `MatSetOption`(mat,`MAT_STRUCTURALLY_SYMMETRIC`,`PETSC_TRUE`) and if it is known to remain structurally
9594:   symmetric after changes to the matrices values one can call `MatSetOption`(mat,`MAT_STRUCTURAL_SYMMETRY_ETERNAL`,`PETSC_TRUE`)

9596: .seealso: [](ch_matrices), `Mat`, `MAT_STRUCTURALLY_SYMMETRIC`, `MAT_STRUCTURAL_SYMMETRY_ETERNAL`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsSymmetric()`, `MatSetOption()`, `MatIsStructurallySymmetricKnown()`
9597: @*/
9598: PetscErrorCode MatIsStructurallySymmetric(Mat A, PetscBool *flg)
9599: {
9600:   PetscFunctionBegin;
9602:   PetscAssertPointer(flg, 2);
9603:   if (A->structurally_symmetric != PETSC_BOOL3_UNKNOWN) {
9604:     *flg = PetscBool3ToBool(A->structurally_symmetric);
9605:   } else {
9606:     PetscUseTypeMethod(A, isstructurallysymmetric, flg);
9607:     PetscCall(MatSetOption(A, MAT_STRUCTURALLY_SYMMETRIC, *flg));
9608:   }
9609:   PetscFunctionReturn(PETSC_SUCCESS);
9610: }

9612: /*@
9613:   MatIsStructurallySymmetricKnown - Checks if a matrix knows if it is structurally symmetric or not and its structurally symmetric state

9615:   Not Collective

9617:   Input Parameter:
9618: . A - the matrix to check

9620:   Output Parameters:
9621: + set - PETSC_TRUE if the matrix knows its structurally symmetric state (this tells you if the next flag is valid)
9622: - flg - the result (only valid if set is PETSC_TRUE)

9624:   Level: advanced

9626:   Notes:
9627:   One can declare that a matrix is structurally symmetric with `MatSetOption`(mat,`MAT_STRUCTURALLY_SYMMETRIC`,`PETSC_TRUE`) and if it is known to remain structurally
9628:   symmetric after changes to the matrices values one can call `MatSetOption`(mat,`MAT_STRUCTURAL_SYMMETRY_ETERNAL`,`PETSC_TRUE`)

9630:   Use `MatIsStructurallySymmetric()` to explicitly check if a matrix is structurally symmetric (this is an expensive operation)

9632: .seealso: [](ch_matrices), `Mat`, `MAT_STRUCTURALLY_SYMMETRIC`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetric()`, `MatIsHermitianKnown()`
9633: @*/
9634: PetscErrorCode MatIsStructurallySymmetricKnown(Mat A, PetscBool *set, PetscBool *flg)
9635: {
9636:   PetscFunctionBegin;
9638:   PetscAssertPointer(set, 2);
9639:   PetscAssertPointer(flg, 3);
9640:   if (A->structurally_symmetric != PETSC_BOOL3_UNKNOWN) {
9641:     *set = PETSC_TRUE;
9642:     *flg = PetscBool3ToBool(A->structurally_symmetric);
9643:   } else {
9644:     *set = PETSC_FALSE;
9645:   }
9646:   PetscFunctionReturn(PETSC_SUCCESS);
9647: }

9649: /*@
9650:   MatStashGetInfo - Gets how many values are currently in the matrix stash, i.e. need
9651:   to be communicated to other processors during the `MatAssemblyBegin()`/`MatAssemblyEnd()` process

9653:   Not Collective

9655:   Input Parameter:
9656: . mat - the matrix

9658:   Output Parameters:
9659: + nstash    - the size of the stash
9660: . reallocs  - the number of additional mallocs incurred.
9661: . bnstash   - the size of the block stash
9662: - breallocs - the number of additional mallocs incurred.in the block stash

9664:   Level: advanced

9666: .seealso: [](ch_matrices), `MatAssemblyBegin()`, `MatAssemblyEnd()`, `Mat`, `MatStashSetInitialSize()`
9667: @*/
9668: PetscErrorCode MatStashGetInfo(Mat mat, PetscInt *nstash, PetscInt *reallocs, PetscInt *bnstash, PetscInt *breallocs)
9669: {
9670:   PetscFunctionBegin;
9671:   PetscCall(MatStashGetInfo_Private(&mat->stash, nstash, reallocs));
9672:   PetscCall(MatStashGetInfo_Private(&mat->bstash, bnstash, breallocs));
9673:   PetscFunctionReturn(PETSC_SUCCESS);
9674: }

9676: /*@
9677:   MatCreateVecs - Get vector(s) compatible with the matrix, i.e. with the same
9678:   parallel layout, `PetscLayout` for rows and columns

9680:   Collective

9682:   Input Parameter:
9683: . mat - the matrix

9685:   Output Parameters:
9686: + right - (optional) vector that the matrix can be multiplied against
9687: - left  - (optional) vector that the matrix vector product can be stored in

9689:   Level: advanced

9691:   Notes:
9692:   The blocksize of the returned vectors is determined by the row and column block sizes set with `MatSetBlockSizes()` or the single blocksize (same for both) set by `MatSetBlockSize()`.

9694:   These are new vectors which are not owned by the mat, they should be destroyed in `VecDestroy()` when no longer needed

9696: .seealso: [](ch_matrices), `Mat`, `Vec`, `VecCreate()`, `VecDestroy()`, `DMCreateGlobalVector()`
9697: @*/
9698: PetscErrorCode MatCreateVecs(Mat mat, Vec *right, Vec *left)
9699: {
9700:   PetscFunctionBegin;
9703:   if (mat->ops->getvecs) {
9704:     PetscUseTypeMethod(mat, getvecs, right, left);
9705:   } else {
9706:     if (right) {
9707:       PetscCheck(mat->cmap->n >= 0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "PetscLayout for columns not yet setup");
9708:       PetscCall(VecCreateWithLayout_Private(mat->cmap, right));
9709:       PetscCall(VecSetType(*right, mat->defaultvectype));
9710: #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_CUDA) || defined(PETSC_HAVE_HIP)
9711:       if (mat->boundtocpu && mat->bindingpropagates) {
9712:         PetscCall(VecSetBindingPropagates(*right, PETSC_TRUE));
9713:         PetscCall(VecBindToCPU(*right, PETSC_TRUE));
9714:       }
9715: #endif
9716:     }
9717:     if (left) {
9718:       PetscCheck(mat->rmap->n >= 0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "PetscLayout for rows not yet setup");
9719:       PetscCall(VecCreateWithLayout_Private(mat->rmap, left));
9720:       PetscCall(VecSetType(*left, mat->defaultvectype));
9721: #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_CUDA) || defined(PETSC_HAVE_HIP)
9722:       if (mat->boundtocpu && mat->bindingpropagates) {
9723:         PetscCall(VecSetBindingPropagates(*left, PETSC_TRUE));
9724:         PetscCall(VecBindToCPU(*left, PETSC_TRUE));
9725:       }
9726: #endif
9727:     }
9728:   }
9729:   PetscFunctionReturn(PETSC_SUCCESS);
9730: }

9732: /*@
9733:   MatFactorInfoInitialize - Initializes a `MatFactorInfo` data structure
9734:   with default values.

9736:   Not Collective

9738:   Input Parameter:
9739: . info - the `MatFactorInfo` data structure

9741:   Level: developer

9743:   Notes:
9744:   The solvers are generally used through the `KSP` and `PC` objects, for example
9745:   `PCLU`, `PCILU`, `PCCHOLESKY`, `PCICC`

9747:   Once the data structure is initialized one may change certain entries as desired for the particular factorization to be performed

9749: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorInfo`
9750: @*/
9751: PetscErrorCode MatFactorInfoInitialize(MatFactorInfo *info)
9752: {
9753:   PetscFunctionBegin;
9754:   PetscCall(PetscMemzero(info, sizeof(MatFactorInfo)));
9755:   PetscFunctionReturn(PETSC_SUCCESS);
9756: }

9758: /*@
9759:   MatFactorSetSchurIS - Set indices corresponding to the Schur complement you wish to have computed

9761:   Collective

9763:   Input Parameters:
9764: + mat - the factored matrix
9765: - is  - the index set defining the Schur indices (0-based)

9767:   Level: advanced

9769:   Notes:
9770:   Call `MatFactorSolveSchurComplement()` or `MatFactorSolveSchurComplementTranspose()` after this call to solve a Schur complement system.

9772:   You can call `MatFactorGetSchurComplement()` or `MatFactorCreateSchurComplement()` after this call.

9774:   This functionality is only supported for `MATSOLVERMUMPS` and `MATSOLVERMKL_PARDISO`

9776: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorGetSchurComplement()`, `MatFactorRestoreSchurComplement()`, `MatFactorCreateSchurComplement()`, `MatFactorSolveSchurComplement()`,
9777:           `MatFactorSolveSchurComplementTranspose()`, `MATSOLVERMUMPS`, `MATSOLVERMKL_PARDISO`
9778: @*/
9779: PetscErrorCode MatFactorSetSchurIS(Mat mat, IS is)
9780: {
9781:   PetscErrorCode (*f)(Mat, IS);

9783:   PetscFunctionBegin;
9788:   PetscCheckSameComm(mat, 1, is, 2);
9789:   PetscCheck(mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Only for factored matrix");
9790:   PetscCall(PetscObjectQueryFunction((PetscObject)mat, "MatFactorSetSchurIS_C", &f));
9791:   PetscCheck(f, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "The selected MatSolverType does not support Schur complement computation. You should use MATSOLVERMUMPS or MATSOLVERMKL_PARDISO");
9792:   PetscCall(MatDestroy(&mat->schur));
9793:   PetscCall((*f)(mat, is));
9794:   PetscCheck(mat->schur, PetscObjectComm((PetscObject)mat), PETSC_ERR_PLIB, "Schur complement has not been created");
9795:   PetscFunctionReturn(PETSC_SUCCESS);
9796: }

9798: /*@
9799:   MatFactorCreateSchurComplement - Create a Schur complement matrix object using Schur data computed during the factorization step

9801:   Logically Collective

9803:   Input Parameters:
9804: + F      - the factored matrix obtained by calling `MatGetFactor()`
9805: . S      - location where to return the Schur complement, can be `NULL`
9806: - status - the status of the Schur complement matrix, can be `NULL`

9808:   Level: advanced

9810:   Notes:
9811:   You must call `MatFactorSetSchurIS()` before calling this routine.

9813:   This functionality is only supported for `MATSOLVERMUMPS` and `MATSOLVERMKL_PARDISO`

9815:   The routine provides a copy of the Schur matrix stored within the solver data structures.
9816:   The caller must destroy the object when it is no longer needed.
9817:   If `MatFactorInvertSchurComplement()` has been called, the routine gets back the inverse.

9819:   Use `MatFactorGetSchurComplement()` to get access to the Schur complement matrix inside the factored matrix instead of making a copy of it (which this function does)

9821:   See `MatCreateSchurComplement()` or `MatGetSchurComplement()` for ways to create virtual or approximate Schur complements.

9823:   Developer Note:
9824:   The reason this routine exists is because the representation of the Schur complement within the factor matrix may be different than a standard PETSc
9825:   matrix representation and we normally do not want to use the time or memory to make a copy as a regular PETSc matrix.

9827: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorGetSchurComplement()`, `MatFactorSchurStatus`, `MATSOLVERMUMPS`, `MATSOLVERMKL_PARDISO`
9828: @*/
9829: PetscErrorCode MatFactorCreateSchurComplement(Mat F, Mat *S, MatFactorSchurStatus *status)
9830: {
9831:   PetscFunctionBegin;
9833:   if (S) PetscAssertPointer(S, 2);
9834:   if (status) PetscAssertPointer(status, 3);
9835:   if (S) {
9836:     PetscErrorCode (*f)(Mat, Mat *);

9838:     PetscCall(PetscObjectQueryFunction((PetscObject)F, "MatFactorCreateSchurComplement_C", &f));
9839:     if (f) {
9840:       PetscCall((*f)(F, S));
9841:     } else {
9842:       PetscCall(MatDuplicate(F->schur, MAT_COPY_VALUES, S));
9843:     }
9844:   }
9845:   if (status) *status = F->schur_status;
9846:   PetscFunctionReturn(PETSC_SUCCESS);
9847: }

9849: /*@
9850:   MatFactorGetSchurComplement - Gets access to a Schur complement matrix using the current Schur data within a factored matrix

9852:   Logically Collective

9854:   Input Parameters:
9855: + F      - the factored matrix obtained by calling `MatGetFactor()`
9856: . S      - location where to return the Schur complement, can be `NULL`
9857: - status - the status of the Schur complement matrix, can be `NULL`

9859:   Level: advanced

9861:   Notes:
9862:   You must call `MatFactorSetSchurIS()` before calling this routine.

9864:   Schur complement mode is currently implemented for sequential matrices with factor type of `MATSOLVERMUMPS`

9866:   The routine returns a the Schur Complement stored within the data structures of the solver.

9868:   If `MatFactorInvertSchurComplement()` has previously been called, the returned matrix is actually the inverse of the Schur complement.

9870:   The returned matrix should not be destroyed; the caller should call `MatFactorRestoreSchurComplement()` when the object is no longer needed.

9872:   Use `MatFactorCreateSchurComplement()` to create a copy of the Schur complement matrix that is within a factored matrix

9874:   See `MatCreateSchurComplement()` or `MatGetSchurComplement()` for ways to create virtual or approximate Schur complements.

9876: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorRestoreSchurComplement()`, `MatFactorCreateSchurComplement()`, `MatFactorSchurStatus`
9877: @*/
9878: PetscErrorCode MatFactorGetSchurComplement(Mat F, Mat *S, MatFactorSchurStatus *status)
9879: {
9880:   PetscFunctionBegin;
9882:   if (S) {
9883:     PetscAssertPointer(S, 2);
9884:     *S = F->schur;
9885:   }
9886:   if (status) {
9887:     PetscAssertPointer(status, 3);
9888:     *status = F->schur_status;
9889:   }
9890:   PetscFunctionReturn(PETSC_SUCCESS);
9891: }

9893: static PetscErrorCode MatFactorUpdateSchurStatus_Private(Mat F)
9894: {
9895:   Mat S = F->schur;

9897:   PetscFunctionBegin;
9898:   switch (F->schur_status) {
9899:   case MAT_FACTOR_SCHUR_UNFACTORED: // fall-through
9900:   case MAT_FACTOR_SCHUR_INVERTED:
9901:     if (S) {
9902:       S->ops->solve             = NULL;
9903:       S->ops->matsolve          = NULL;
9904:       S->ops->solvetranspose    = NULL;
9905:       S->ops->matsolvetranspose = NULL;
9906:       S->ops->solveadd          = NULL;
9907:       S->ops->solvetransposeadd = NULL;
9908:       S->factortype             = MAT_FACTOR_NONE;
9909:       PetscCall(PetscFree(S->solvertype));
9910:     }
9911:   case MAT_FACTOR_SCHUR_FACTORED: // fall-through
9912:     break;
9913:   default:
9914:     SETERRQ(PetscObjectComm((PetscObject)F), PETSC_ERR_SUP, "Unhandled MatFactorSchurStatus %d", F->schur_status);
9915:   }
9916:   PetscFunctionReturn(PETSC_SUCCESS);
9917: }

9919: /*@
9920:   MatFactorRestoreSchurComplement - Restore the Schur complement matrix object obtained from a call to `MatFactorGetSchurComplement()`

9922:   Logically Collective

9924:   Input Parameters:
9925: + F      - the factored matrix obtained by calling `MatGetFactor()`
9926: . S      - location where the Schur complement is stored
9927: - status - the status of the Schur complement matrix (see `MatFactorSchurStatus`)

9929:   Level: advanced

9931: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorCreateSchurComplement()`, `MatFactorSchurStatus`
9932: @*/
9933: PetscErrorCode MatFactorRestoreSchurComplement(Mat F, Mat *S, MatFactorSchurStatus status)
9934: {
9935:   PetscFunctionBegin;
9937:   if (S) {
9939:     *S = NULL;
9940:   }
9941:   F->schur_status = status;
9942:   PetscCall(MatFactorUpdateSchurStatus_Private(F));
9943:   PetscFunctionReturn(PETSC_SUCCESS);
9944: }

9946: /*@
9947:   MatFactorSolveSchurComplementTranspose - Solve the transpose of the Schur complement system computed during the factorization step

9949:   Logically Collective

9951:   Input Parameters:
9952: + F   - the factored matrix obtained by calling `MatGetFactor()`
9953: . rhs - location where the right-hand side of the Schur complement system is stored
9954: - sol - location where the solution of the Schur complement system has to be returned

9956:   Level: advanced

9958:   Notes:
9959:   The sizes of the vectors should match the size of the Schur complement

9961:   Must be called after `MatFactorSetSchurIS()`

9963: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorSolveSchurComplement()`
9964: @*/
9965: PetscErrorCode MatFactorSolveSchurComplementTranspose(Mat F, Vec rhs, Vec sol)
9966: {
9967:   PetscFunctionBegin;
9974:   PetscCheckSameComm(F, 1, rhs, 2);
9975:   PetscCheckSameComm(F, 1, sol, 3);
9976:   PetscCall(MatFactorFactorizeSchurComplement(F));
9977:   switch (F->schur_status) {
9978:   case MAT_FACTOR_SCHUR_FACTORED:
9979:     PetscCall(MatSolveTranspose(F->schur, rhs, sol));
9980:     break;
9981:   case MAT_FACTOR_SCHUR_INVERTED:
9982:     PetscCall(MatMultTranspose(F->schur, rhs, sol));
9983:     break;
9984:   default:
9985:     SETERRQ(PetscObjectComm((PetscObject)F), PETSC_ERR_SUP, "Unhandled MatFactorSchurStatus %d", F->schur_status);
9986:   }
9987:   PetscFunctionReturn(PETSC_SUCCESS);
9988: }

9990: /*@
9991:   MatFactorSolveSchurComplement - Solve the Schur complement system computed during the factorization step

9993:   Logically Collective

9995:   Input Parameters:
9996: + F   - the factored matrix obtained by calling `MatGetFactor()`
9997: . rhs - location where the right-hand side of the Schur complement system is stored
9998: - sol - location where the solution of the Schur complement system has to be returned

10000:   Level: advanced

10002:   Notes:
10003:   The sizes of the vectors should match the size of the Schur complement

10005:   Must be called after `MatFactorSetSchurIS()`

10007: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorSolveSchurComplementTranspose()`
10008: @*/
10009: PetscErrorCode MatFactorSolveSchurComplement(Mat F, Vec rhs, Vec sol)
10010: {
10011:   PetscFunctionBegin;
10018:   PetscCheckSameComm(F, 1, rhs, 2);
10019:   PetscCheckSameComm(F, 1, sol, 3);
10020:   PetscCall(MatFactorFactorizeSchurComplement(F));
10021:   switch (F->schur_status) {
10022:   case MAT_FACTOR_SCHUR_FACTORED:
10023:     PetscCall(MatSolve(F->schur, rhs, sol));
10024:     break;
10025:   case MAT_FACTOR_SCHUR_INVERTED:
10026:     PetscCall(MatMult(F->schur, rhs, sol));
10027:     break;
10028:   default:
10029:     SETERRQ(PetscObjectComm((PetscObject)F), PETSC_ERR_SUP, "Unhandled MatFactorSchurStatus %d", F->schur_status);
10030:   }
10031:   PetscFunctionReturn(PETSC_SUCCESS);
10032: }

10034: PETSC_EXTERN PetscErrorCode MatSeqDenseInvertFactors_Private(Mat);
10035: #if PetscDefined(HAVE_CUDA)
10036: PETSC_SINGLE_LIBRARY_INTERN PetscErrorCode MatSeqDenseCUDAInvertFactors_Internal(Mat);
10037: #endif

10039: /* Schur status updated in the interface */
10040: static PetscErrorCode MatFactorInvertSchurComplement_Private(Mat F)
10041: {
10042:   Mat S = F->schur;

10044:   PetscFunctionBegin;
10045:   if (S) {
10046:     PetscMPIInt size;
10047:     PetscBool   isdense, isdensecuda;

10049:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)S), &size));
10050:     PetscCheck(size <= 1, PetscObjectComm((PetscObject)S), PETSC_ERR_SUP, "Not yet implemented");
10051:     PetscCall(PetscObjectTypeCompare((PetscObject)S, MATSEQDENSE, &isdense));
10052:     PetscCall(PetscObjectTypeCompare((PetscObject)S, MATSEQDENSECUDA, &isdensecuda));
10053:     PetscCheck(isdense || isdensecuda, PetscObjectComm((PetscObject)S), PETSC_ERR_SUP, "Not implemented for type %s", ((PetscObject)S)->type_name);
10054:     PetscCall(PetscLogEventBegin(MAT_FactorInvS, F, 0, 0, 0));
10055:     if (isdense) {
10056:       PetscCall(MatSeqDenseInvertFactors_Private(S));
10057:     } else if (isdensecuda) {
10058: #if defined(PETSC_HAVE_CUDA)
10059:       PetscCall(MatSeqDenseCUDAInvertFactors_Internal(S));
10060: #endif
10061:     }
10062:     // HIP??????????????
10063:     PetscCall(PetscLogEventEnd(MAT_FactorInvS, F, 0, 0, 0));
10064:   }
10065:   PetscFunctionReturn(PETSC_SUCCESS);
10066: }

10068: /*@
10069:   MatFactorInvertSchurComplement - Invert the Schur complement matrix computed during the factorization step

10071:   Logically Collective

10073:   Input Parameter:
10074: . F - the factored matrix obtained by calling `MatGetFactor()`

10076:   Level: advanced

10078:   Notes:
10079:   Must be called after `MatFactorSetSchurIS()`.

10081:   Call `MatFactorGetSchurComplement()` or  `MatFactorCreateSchurComplement()` AFTER this call to actually compute the inverse and get access to it.

10083: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorGetSchurComplement()`, `MatFactorCreateSchurComplement()`
10084: @*/
10085: PetscErrorCode MatFactorInvertSchurComplement(Mat F)
10086: {
10087:   PetscFunctionBegin;
10090:   if (F->schur_status == MAT_FACTOR_SCHUR_INVERTED) PetscFunctionReturn(PETSC_SUCCESS);
10091:   PetscCall(MatFactorFactorizeSchurComplement(F));
10092:   PetscCall(MatFactorInvertSchurComplement_Private(F));
10093:   F->schur_status = MAT_FACTOR_SCHUR_INVERTED;
10094:   PetscFunctionReturn(PETSC_SUCCESS);
10095: }

10097: /*@
10098:   MatFactorFactorizeSchurComplement - Factorize the Schur complement matrix computed during the factorization step

10100:   Logically Collective

10102:   Input Parameter:
10103: . F - the factored matrix obtained by calling `MatGetFactor()`

10105:   Level: advanced

10107:   Note:
10108:   Must be called after `MatFactorSetSchurIS()`

10110: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorInvertSchurComplement()`
10111: @*/
10112: PetscErrorCode MatFactorFactorizeSchurComplement(Mat F)
10113: {
10114:   MatFactorInfo info;

10116:   PetscFunctionBegin;
10119:   if (F->schur_status == MAT_FACTOR_SCHUR_INVERTED || F->schur_status == MAT_FACTOR_SCHUR_FACTORED) PetscFunctionReturn(PETSC_SUCCESS);
10120:   PetscCall(PetscLogEventBegin(MAT_FactorFactS, F, 0, 0, 0));
10121:   PetscCall(PetscMemzero(&info, sizeof(MatFactorInfo)));
10122:   if (F->factortype == MAT_FACTOR_CHOLESKY) { /* LDL^t regarded as Cholesky */
10123:     PetscCall(MatCholeskyFactor(F->schur, NULL, &info));
10124:   } else {
10125:     PetscCall(MatLUFactor(F->schur, NULL, NULL, &info));
10126:   }
10127:   PetscCall(PetscLogEventEnd(MAT_FactorFactS, F, 0, 0, 0));
10128:   F->schur_status = MAT_FACTOR_SCHUR_FACTORED;
10129:   PetscFunctionReturn(PETSC_SUCCESS);
10130: }

10132: /*@
10133:   MatPtAP - Creates the matrix product $C = P^T * A * P$

10135:   Neighbor-wise Collective

10137:   Input Parameters:
10138: + A     - the matrix
10139: . P     - the projection matrix
10140: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10141: - fill  - expected fill as ratio of nnz(C)/(nnz(A) + nnz(P)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if you do not have a good estimate
10142:           if the result is a dense matrix this is irrelevant

10144:   Output Parameter:
10145: . C - the product matrix

10147:   Level: intermediate

10149:   Notes:
10150:   C will be created and must be destroyed by the user with `MatDestroy()`.

10152:   An alternative approach to this function is to use `MatProductCreate()` and set the desired options before the computation is done

10154:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10156:   Developer Note:
10157:   For matrix types without special implementation the function fallbacks to `MatMatMult()` followed by `MatTransposeMatMult()`.

10159: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MatMatMult()`, `MatRARt()`
10160: @*/
10161: PetscErrorCode MatPtAP(Mat A, Mat P, MatReuse scall, PetscReal fill, Mat *C)
10162: {
10163:   PetscFunctionBegin;
10164:   if (scall == MAT_REUSE_MATRIX) MatCheckProduct(*C, 5);
10165:   PetscCheck(scall != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Inplace product not supported");

10167:   if (scall == MAT_INITIAL_MATRIX) {
10168:     PetscCall(MatProductCreate(A, P, NULL, C));
10169:     PetscCall(MatProductSetType(*C, MATPRODUCT_PtAP));
10170:     PetscCall(MatProductSetAlgorithm(*C, "default"));
10171:     PetscCall(MatProductSetFill(*C, fill));

10173:     (*C)->product->api_user = PETSC_TRUE;
10174:     PetscCall(MatProductSetFromOptions(*C));
10175:     PetscCheck((*C)->ops->productsymbolic, PetscObjectComm((PetscObject)*C), PETSC_ERR_SUP, "MatProduct %s not supported for A %s and P %s", MatProductTypes[MATPRODUCT_PtAP], ((PetscObject)A)->type_name, ((PetscObject)P)->type_name);
10176:     PetscCall(MatProductSymbolic(*C));
10177:   } else { /* scall == MAT_REUSE_MATRIX */
10178:     PetscCall(MatProductReplaceMats(A, P, NULL, *C));
10179:   }

10181:   PetscCall(MatProductNumeric(*C));
10182:   (*C)->symmetric = A->symmetric;
10183:   (*C)->spd       = A->spd;
10184:   PetscFunctionReturn(PETSC_SUCCESS);
10185: }

10187: /*@
10188:   MatRARt - Creates the matrix product $C = R * A * R^T$

10190:   Neighbor-wise Collective

10192:   Input Parameters:
10193: + A     - the matrix
10194: . R     - the projection matrix
10195: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10196: - fill  - expected fill as ratio of nnz(C)/nnz(A), use `PETSC_DETERMINE` or `PETSC_CURRENT` if you do not have a good estimate
10197:           if the result is a dense matrix this is irrelevant

10199:   Output Parameter:
10200: . C - the product matrix

10202:   Level: intermediate

10204:   Notes:
10205:   `C` will be created and must be destroyed by the user with `MatDestroy()`.

10207:   An alternative approach to this function is to use `MatProductCreate()` and set the desired options before the computation is done

10209:   This routine is currently only implemented for pairs of `MATAIJ` matrices and classes
10210:   which inherit from `MATAIJ`. Due to PETSc sparse matrix block row distribution among processes,
10211:   the parallel `MatRARt()` is implemented computing the explicit transpose of `R`, which can be very expensive.
10212:   We recommend using `MatPtAP()` when possible.

10214:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10216: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MatMatMult()`, `MatPtAP()`
10217: @*/
10218: PetscErrorCode MatRARt(Mat A, Mat R, MatReuse scall, PetscReal fill, Mat *C)
10219: {
10220:   PetscFunctionBegin;
10221:   if (scall == MAT_REUSE_MATRIX) MatCheckProduct(*C, 5);
10222:   PetscCheck(scall != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Inplace product not supported");

10224:   if (scall == MAT_INITIAL_MATRIX) {
10225:     PetscCall(MatProductCreate(A, R, NULL, C));
10226:     PetscCall(MatProductSetType(*C, MATPRODUCT_RARt));
10227:     PetscCall(MatProductSetAlgorithm(*C, "default"));
10228:     PetscCall(MatProductSetFill(*C, fill));

10230:     (*C)->product->api_user = PETSC_TRUE;
10231:     PetscCall(MatProductSetFromOptions(*C));
10232:     PetscCheck((*C)->ops->productsymbolic, PetscObjectComm((PetscObject)*C), PETSC_ERR_SUP, "MatProduct %s not supported for A %s and R %s", MatProductTypes[MATPRODUCT_RARt], ((PetscObject)A)->type_name, ((PetscObject)R)->type_name);
10233:     PetscCall(MatProductSymbolic(*C));
10234:   } else { /* scall == MAT_REUSE_MATRIX */
10235:     PetscCall(MatProductReplaceMats(A, R, NULL, *C));
10236:   }

10238:   PetscCall(MatProductNumeric(*C));
10239:   if (A->symmetric == PETSC_BOOL3_TRUE) PetscCall(MatSetOption(*C, MAT_SYMMETRIC, PETSC_TRUE));
10240:   PetscFunctionReturn(PETSC_SUCCESS);
10241: }

10243: static PetscErrorCode MatProduct_Private(Mat A, Mat B, MatReuse scall, PetscReal fill, MatProductType ptype, Mat *C)
10244: {
10245:   PetscBool flg = PETSC_TRUE;

10247:   PetscFunctionBegin;
10248:   PetscCheck(scall != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "MAT_INPLACE_MATRIX product not supported");
10249:   if (scall == MAT_INITIAL_MATRIX) {
10250:     PetscCall(PetscInfo(A, "Calling MatProduct API with MAT_INITIAL_MATRIX and product type %s\n", MatProductTypes[ptype]));
10251:     PetscCall(MatProductCreate(A, B, NULL, C));
10252:     PetscCall(MatProductSetAlgorithm(*C, MATPRODUCTALGORITHMDEFAULT));
10253:     PetscCall(MatProductSetFill(*C, fill));
10254:   } else { /* scall == MAT_REUSE_MATRIX */
10255:     Mat_Product *product = (*C)->product;

10257:     PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)*C, &flg, MATSEQDENSE, MATMPIDENSE, ""));
10258:     if (flg && product && product->type != ptype) {
10259:       PetscCall(MatProductClear(*C));
10260:       product = NULL;
10261:     }
10262:     PetscCall(PetscInfo(A, "Calling MatProduct API with MAT_REUSE_MATRIX %s product present and product type %s\n", product ? "with" : "without", MatProductTypes[ptype]));
10263:     if (!product) { /* user provide the dense matrix *C without calling MatProductCreate() or reusing it from previous calls */
10264:       PetscCheck(flg, PetscObjectComm((PetscObject)*C), PETSC_ERR_SUP, "Call MatProductCreate() first");
10265:       PetscCall(MatProductCreate_Private(A, B, NULL, *C));
10266:       product        = (*C)->product;
10267:       product->fill  = fill;
10268:       product->clear = PETSC_TRUE;
10269:     } else { /* user may change input matrices A or B when MAT_REUSE_MATRIX */
10270:       flg = PETSC_FALSE;
10271:       PetscCall(MatProductReplaceMats(A, B, NULL, *C));
10272:     }
10273:   }
10274:   if (flg) {
10275:     (*C)->product->api_user = PETSC_TRUE;
10276:     PetscCall(MatProductSetType(*C, ptype));
10277:     PetscCall(MatProductSetFromOptions(*C));
10278:     PetscCall(MatProductSymbolic(*C));
10279:   }
10280:   PetscCall(MatProductNumeric(*C));
10281:   PetscFunctionReturn(PETSC_SUCCESS);
10282: }

10284: /*@
10285:   MatMatMult - Performs matrix-matrix multiplication C=A*B.

10287:   Neighbor-wise Collective

10289:   Input Parameters:
10290: + A     - the left matrix
10291: . B     - the right matrix
10292: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10293: - fill  - expected fill as ratio of nnz(C)/(nnz(A) + nnz(B)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if you do not have a good estimate
10294:           if the result is a dense matrix this is irrelevant

10296:   Output Parameter:
10297: . C - the product matrix

10299:   Notes:
10300:   Unless scall is `MAT_REUSE_MATRIX` C will be created.

10302:   `MAT_REUSE_MATRIX` can only be used if the matrices A and B have the same nonzero pattern as in the previous call and C was obtained from a previous
10303:   call to this function with `MAT_INITIAL_MATRIX`.

10305:   To determine the correct fill value, run with `-info` and search for the string "Fill ratio" to see the value actually needed.

10307:   In the special case where matrix `B` (and hence `C`) are dense you can create the correctly sized matrix `C` yourself and then call this routine with `MAT_REUSE_MATRIX`,
10308:   rather than first having `MatMatMult()` create it for you. You can NEVER do this if the matrix `C` is sparse.

10310:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10312:   Example of Usage:
10313: .vb
10314:      MatProductCreate(A,B,NULL,&C);
10315:      MatProductSetType(C,MATPRODUCT_AB);
10316:      MatProductSymbolic(C);
10317:      MatProductNumeric(C); // compute C=A * B
10318:      MatProductReplaceMats(A1,B1,NULL,C); // compute C=A1 * B1
10319:      MatProductNumeric(C);
10320:      MatProductReplaceMats(A2,NULL,NULL,C); // compute C=A2 * B1
10321:      MatProductNumeric(C);
10322: .ve

10324:   Level: intermediate

10326: .seealso: [](ch_matrices), `Mat`, `MatProductType`, `MATPRODUCT_AB`, `MatTransposeMatMult()`, `MatMatTransposeMult()`, `MatPtAP()`, `MatProductCreate()`, `MatProductSymbolic()`, `MatProductReplaceMats()`, `MatProductNumeric()`
10327: @*/
10328: PetscErrorCode MatMatMult(Mat A, Mat B, MatReuse scall, PetscReal fill, Mat *C)
10329: {
10330:   PetscFunctionBegin;
10331:   PetscCall(MatProduct_Private(A, B, scall, fill, MATPRODUCT_AB, C));
10332:   PetscFunctionReturn(PETSC_SUCCESS);
10333: }

10335: /*@
10336:   MatMatTransposeMult - Performs matrix-matrix multiplication $C = A*B^T$.

10338:   Neighbor-wise Collective

10340:   Input Parameters:
10341: + A     - the left matrix
10342: . B     - the right matrix
10343: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10344: - fill  - expected fill as ratio of nnz(C)/(nnz(A) + nnz(B)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if not known

10346:   Output Parameter:
10347: . C - the product matrix

10349:   Options Database Key:
10350: . -matmattransmult_mpidense_mpidense_via {allgatherv,cyclic} - Choose between algorithms for `MATMPIDENSE` matrices: the
10351:               first redundantly copies the transposed `B` matrix on each process and requires O(log P) communication complexity;
10352:               the second never stores more than one portion of the `B` matrix at a time but requires O(P) communication complexity.

10354:   Level: intermediate

10356:   Notes:
10357:   C will be created if `MAT_INITIAL_MATRIX` and must be destroyed by the user with `MatDestroy()`.

10359:   `MAT_REUSE_MATRIX` can only be used if the matrices A and B have the same nonzero pattern as in the previous call

10361:   To determine the correct fill value, run with -info and search for the string "Fill ratio" to see the value
10362:   actually needed.

10364:   This routine is currently only implemented for pairs of `MATSEQAIJ` matrices, for the `MATSEQDENSE` class,
10365:   and for pairs of `MATMPIDENSE` matrices.

10367:   This routine is shorthand for using `MatProductCreate()` with the `MatProductType` of `MATPRODUCT_ABt`

10369:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10371: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MATPRODUCT_ABt`, `MatMatMult()`, `MatTransposeMatMult()` `MatPtAP()`, `MatProductAlgorithm`, `MatProductType`
10372: @*/
10373: PetscErrorCode MatMatTransposeMult(Mat A, Mat B, MatReuse scall, PetscReal fill, Mat *C)
10374: {
10375:   PetscFunctionBegin;
10376:   PetscCall(MatProduct_Private(A, B, scall, fill, MATPRODUCT_ABt, C));
10377:   if (A == B) PetscCall(MatSetOption(*C, MAT_SYMMETRIC, PETSC_TRUE));
10378:   PetscFunctionReturn(PETSC_SUCCESS);
10379: }

10381: /*@
10382:   MatTransposeMatMult - Performs matrix-matrix multiplication $C = A^T*B$.

10384:   Neighbor-wise Collective

10386:   Input Parameters:
10387: + A     - the left matrix
10388: . B     - the right matrix
10389: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10390: - fill  - expected fill as ratio of nnz(C)/(nnz(A) + nnz(B)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if not known

10392:   Output Parameter:
10393: . C - the product matrix

10395:   Level: intermediate

10397:   Notes:
10398:   `C` will be created if `MAT_INITIAL_MATRIX` and must be destroyed by the user with `MatDestroy()`.

10400:   `MAT_REUSE_MATRIX` can only be used if the matrices A and B have the same nonzero pattern as in the previous call.

10402:   This routine is shorthand for using `MatProductCreate()` with the `MatProductType` of `MATPRODUCT_AtB`

10404:   To determine the correct fill value, run with -info and search for the string "Fill ratio" to see the value
10405:   actually needed.

10407:   This routine is currently implemented for pairs of `MATAIJ` matrices and pairs of `MATSEQDENSE` matrices and classes
10408:   which inherit from `MATSEQAIJ`.  `C` will be of the same type as the input matrices.

10410:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10412: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MATPRODUCT_AtB`, `MatMatMult()`, `MatMatTransposeMult()`, `MatPtAP()`
10413: @*/
10414: PetscErrorCode MatTransposeMatMult(Mat A, Mat B, MatReuse scall, PetscReal fill, Mat *C)
10415: {
10416:   PetscFunctionBegin;
10417:   PetscCall(MatProduct_Private(A, B, scall, fill, MATPRODUCT_AtB, C));
10418:   PetscFunctionReturn(PETSC_SUCCESS);
10419: }

10421: /*@
10422:   MatMatMatMult - Performs matrix-matrix-matrix multiplication D=A*B*C.

10424:   Neighbor-wise Collective

10426:   Input Parameters:
10427: + A     - the left matrix
10428: . B     - the middle matrix
10429: . C     - the right matrix
10430: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10431: - fill  - expected fill as ratio of nnz(D)/(nnz(A) + nnz(B)+nnz(C)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if you do not have a good estimate
10432:           if the result is a dense matrix this is irrelevant

10434:   Output Parameter:
10435: . D - the product matrix

10437:   Level: intermediate

10439:   Notes:
10440:   Unless `scall` is `MAT_REUSE_MATRIX` `D` will be created.

10442:   `MAT_REUSE_MATRIX` can only be used if the matrices `A`, `B`, and `C` have the same nonzero pattern as in the previous call

10444:   This routine is shorthand for using `MatProductCreate()` with the `MatProductType` of `MATPRODUCT_ABC`

10446:   To determine the correct fill value, run with `-info` and search for the string "Fill ratio" to see the value
10447:   actually needed.

10449:   If you have many matrices with the same non-zero structure to multiply, you
10450:   should use `MAT_REUSE_MATRIX` in all calls but the first

10452:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10454: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MATPRODUCT_ABC`, `MatMatMult`, `MatPtAP()`, `MatMatTransposeMult()`, `MatTransposeMatMult()`
10455: @*/
10456: PetscErrorCode MatMatMatMult(Mat A, Mat B, Mat C, MatReuse scall, PetscReal fill, Mat *D)
10457: {
10458:   PetscFunctionBegin;
10459:   if (scall == MAT_REUSE_MATRIX) MatCheckProduct(*D, 6);
10460:   PetscCheck(scall != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Inplace product not supported");

10462:   if (scall == MAT_INITIAL_MATRIX) {
10463:     PetscCall(MatProductCreate(A, B, C, D));
10464:     PetscCall(MatProductSetType(*D, MATPRODUCT_ABC));
10465:     PetscCall(MatProductSetAlgorithm(*D, "default"));
10466:     PetscCall(MatProductSetFill(*D, fill));

10468:     (*D)->product->api_user = PETSC_TRUE;
10469:     PetscCall(MatProductSetFromOptions(*D));
10470:     PetscCheck((*D)->ops->productsymbolic, PetscObjectComm((PetscObject)*D), PETSC_ERR_SUP, "MatProduct %s not supported for A %s, B %s and C %s", MatProductTypes[MATPRODUCT_ABC], ((PetscObject)A)->type_name, ((PetscObject)B)->type_name,
10471:                ((PetscObject)C)->type_name);
10472:     PetscCall(MatProductSymbolic(*D));
10473:   } else { /* user may change input matrices when REUSE */
10474:     PetscCall(MatProductReplaceMats(A, B, C, *D));
10475:   }
10476:   PetscCall(MatProductNumeric(*D));
10477:   PetscFunctionReturn(PETSC_SUCCESS);
10478: }

10480: /*@
10481:   MatCreateRedundantMatrix - Create redundant matrices and put them into processors of subcommunicators.

10483:   Collective

10485:   Input Parameters:
10486: + mat      - the matrix
10487: . nsubcomm - the number of subcommunicators (= number of redundant parallel or sequential matrices)
10488: . subcomm  - MPI communicator split from the communicator where mat resides in (or `MPI_COMM_NULL` if nsubcomm is used)
10489: - reuse    - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

10491:   Output Parameter:
10492: . matredundant - redundant matrix

10494:   Level: advanced

10496:   Notes:
10497:   `MAT_REUSE_MATRIX` can only be used when the nonzero structure of the
10498:   original matrix has not changed from that last call to `MatCreateRedundantMatrix()`.

10500:   This routine creates the duplicated matrices in the subcommunicators; you should NOT create them before
10501:   calling it.

10503:   `PetscSubcommCreate()` can be used to manage the creation of the subcomm but need not be.

10505: .seealso: [](ch_matrices), `Mat`, `MatDestroy()`, `PetscSubcommCreate()`, `PetscSubcomm`
10506: @*/
10507: PetscErrorCode MatCreateRedundantMatrix(Mat mat, PetscInt nsubcomm, MPI_Comm subcomm, MatReuse reuse, Mat *matredundant)
10508: {
10509:   MPI_Comm       comm;
10510:   PetscMPIInt    size;
10511:   PetscInt       mloc_sub, nloc_sub, rstart, rend, M = mat->rmap->N, N = mat->cmap->N, bs = mat->rmap->bs;
10512:   Mat_Redundant *redund     = NULL;
10513:   PetscSubcomm   psubcomm   = NULL;
10514:   MPI_Comm       subcomm_in = subcomm;
10515:   Mat           *matseq;
10516:   IS             isrow, iscol;
10517:   PetscBool      newsubcomm = PETSC_FALSE;

10519:   PetscFunctionBegin;
10521:   if (nsubcomm && reuse == MAT_REUSE_MATRIX) {
10522:     PetscAssertPointer(*matredundant, 5);
10524:   }

10526:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size));
10527:   if (size == 1 || nsubcomm == 1) {
10528:     if (reuse == MAT_INITIAL_MATRIX) {
10529:       PetscCall(MatDuplicate(mat, MAT_COPY_VALUES, matredundant));
10530:     } else {
10531:       PetscCheck(*matredundant != mat, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MAT_REUSE_MATRIX means reuse the matrix passed in as the final argument, not the original matrix");
10532:       PetscCall(MatCopy(mat, *matredundant, SAME_NONZERO_PATTERN));
10533:     }
10534:     PetscFunctionReturn(PETSC_SUCCESS);
10535:   }

10537:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
10538:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
10539:   MatCheckPreallocated(mat, 1);

10541:   PetscCall(PetscLogEventBegin(MAT_RedundantMat, mat, 0, 0, 0));
10542:   if (subcomm_in == MPI_COMM_NULL && reuse == MAT_INITIAL_MATRIX) { /* get subcomm if user does not provide subcomm */
10543:     /* create psubcomm, then get subcomm */
10544:     PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
10545:     PetscCallMPI(MPI_Comm_size(comm, &size));
10546:     PetscCheck(nsubcomm >= 1 && nsubcomm <= size, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "nsubcomm must between 1 and %d", size);

10548:     PetscCall(PetscSubcommCreate(comm, &psubcomm));
10549:     PetscCall(PetscSubcommSetNumber(psubcomm, nsubcomm));
10550:     PetscCall(PetscSubcommSetType(psubcomm, PETSC_SUBCOMM_CONTIGUOUS));
10551:     PetscCall(PetscSubcommSetFromOptions(psubcomm));
10552:     PetscCall(PetscCommDuplicate(PetscSubcommChild(psubcomm), &subcomm, NULL));
10553:     newsubcomm = PETSC_TRUE;
10554:     PetscCall(PetscSubcommDestroy(&psubcomm));
10555:   }

10557:   /* get isrow, iscol and a local sequential matrix matseq[0] */
10558:   if (reuse == MAT_INITIAL_MATRIX) {
10559:     mloc_sub = PETSC_DECIDE;
10560:     nloc_sub = PETSC_DECIDE;
10561:     if (bs < 1) {
10562:       PetscCall(PetscSplitOwnership(subcomm, &mloc_sub, &M));
10563:       PetscCall(PetscSplitOwnership(subcomm, &nloc_sub, &N));
10564:     } else {
10565:       PetscCall(PetscSplitOwnershipBlock(subcomm, bs, &mloc_sub, &M));
10566:       PetscCall(PetscSplitOwnershipBlock(subcomm, bs, &nloc_sub, &N));
10567:     }
10568:     PetscCallMPI(MPI_Scan(&mloc_sub, &rend, 1, MPIU_INT, MPI_SUM, subcomm));
10569:     rstart = rend - mloc_sub;
10570:     PetscCall(ISCreateStride(PETSC_COMM_SELF, mloc_sub, rstart, 1, &isrow));
10571:     PetscCall(ISCreateStride(PETSC_COMM_SELF, N, 0, 1, &iscol));
10572:     PetscCall(ISSetIdentity(iscol));
10573:   } else { /* reuse == MAT_REUSE_MATRIX */
10574:     PetscCheck(*matredundant != mat, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MAT_REUSE_MATRIX means reuse the matrix passed in as the final argument, not the original matrix");
10575:     /* retrieve subcomm */
10576:     PetscCall(PetscObjectGetComm((PetscObject)*matredundant, &subcomm));
10577:     redund = (*matredundant)->redundant;
10578:     isrow  = redund->isrow;
10579:     iscol  = redund->iscol;
10580:     matseq = redund->matseq;
10581:   }
10582:   PetscCall(MatCreateSubMatrices(mat, 1, &isrow, &iscol, reuse, &matseq));

10584:   /* get matredundant over subcomm */
10585:   if (reuse == MAT_INITIAL_MATRIX) {
10586:     PetscCall(MatCreateMPIMatConcatenateSeqMat(subcomm, matseq[0], nloc_sub, reuse, matredundant));

10588:     /* create a supporting struct and attach it to C for reuse */
10589:     PetscCall(PetscNew(&redund));
10590:     (*matredundant)->redundant = redund;
10591:     redund->isrow              = isrow;
10592:     redund->iscol              = iscol;
10593:     redund->matseq             = matseq;
10594:     if (newsubcomm) {
10595:       redund->subcomm = subcomm;
10596:     } else {
10597:       redund->subcomm = MPI_COMM_NULL;
10598:     }
10599:   } else {
10600:     PetscCall(MatCreateMPIMatConcatenateSeqMat(subcomm, matseq[0], PETSC_DECIDE, reuse, matredundant));
10601:   }
10602: #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_CUDA) || defined(PETSC_HAVE_HIP)
10603:   if (matseq[0]->boundtocpu && matseq[0]->bindingpropagates) {
10604:     PetscCall(MatBindToCPU(*matredundant, PETSC_TRUE));
10605:     PetscCall(MatSetBindingPropagates(*matredundant, PETSC_TRUE));
10606:   }
10607: #endif
10608:   PetscCall(PetscLogEventEnd(MAT_RedundantMat, mat, 0, 0, 0));
10609:   PetscFunctionReturn(PETSC_SUCCESS);
10610: }

10612: /*@C
10613:   MatGetMultiProcBlock - Create multiple 'parallel submatrices' from
10614:   a given `Mat`. Each submatrix can span multiple procs.

10616:   Collective

10618:   Input Parameters:
10619: + mat     - the matrix
10620: . subComm - the sub communicator obtained as if by `MPI_Comm_split(PetscObjectComm((PetscObject)mat))`
10621: - scall   - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

10623:   Output Parameter:
10624: . subMat - parallel sub-matrices each spanning a given `subcomm`

10626:   Level: advanced

10628:   Notes:
10629:   The submatrix partition across processors is dictated by `subComm` a
10630:   communicator obtained by `MPI_comm_split()` or via `PetscSubcommCreate()`. The `subComm`
10631:   is not restricted to be grouped with consecutive original MPI processes.

10633:   Due the `MPI_Comm_split()` usage, the parallel layout of the submatrices
10634:   map directly to the layout of the original matrix [wrt the local
10635:   row,col partitioning]. So the original 'DiagonalMat' naturally maps
10636:   into the 'DiagonalMat' of the `subMat`, hence it is used directly from
10637:   the `subMat`. However the offDiagMat looses some columns - and this is
10638:   reconstructed with `MatSetValues()`

10640:   This is used by `PCBJACOBI` when a single block spans multiple MPI processes.

10642: .seealso: [](ch_matrices), `Mat`, `MatCreateRedundantMatrix()`, `MatCreateSubMatrices()`, `PCBJACOBI`
10643: @*/
10644: PetscErrorCode MatGetMultiProcBlock(Mat mat, MPI_Comm subComm, MatReuse scall, Mat *subMat)
10645: {
10646:   PetscMPIInt commsize, subCommSize;

10648:   PetscFunctionBegin;
10649:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &commsize));
10650:   PetscCallMPI(MPI_Comm_size(subComm, &subCommSize));
10651:   PetscCheck(subCommSize <= commsize, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "CommSize %d < SubCommZize %d", commsize, subCommSize);

10653:   PetscCheck(scall != MAT_REUSE_MATRIX || *subMat != mat, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MAT_REUSE_MATRIX means reuse the matrix passed in as the final argument, not the original matrix");
10654:   PetscCall(PetscLogEventBegin(MAT_GetMultiProcBlock, mat, 0, 0, 0));
10655:   PetscUseTypeMethod(mat, getmultiprocblock, subComm, scall, subMat);
10656:   PetscCall(PetscLogEventEnd(MAT_GetMultiProcBlock, mat, 0, 0, 0));
10657:   PetscFunctionReturn(PETSC_SUCCESS);
10658: }

10660: /*@
10661:   MatGetLocalSubMatrix - Gets a reference to a submatrix specified in local numbering

10663:   Not Collective

10665:   Input Parameters:
10666: + mat   - matrix to extract local submatrix from
10667: . isrow - local row indices for submatrix
10668: - iscol - local column indices for submatrix

10670:   Output Parameter:
10671: . submat - the submatrix

10673:   Level: intermediate

10675:   Notes:
10676:   `submat` should be disposed of with `MatRestoreLocalSubMatrix()`.

10678:   Depending on the format of `mat`, the returned `submat` may not implement `MatMult()`.  Its communicator may be
10679:   the same as `mat`, it may be `PETSC_COMM_SELF`, or some other sub-communictor of `mat`'s.

10681:   `submat` always implements `MatSetValuesLocal()`.  If `isrow` and `iscol` have the same block size, then
10682:   `MatSetValuesBlockedLocal()` will also be implemented.

10684:   `mat` must have had a `ISLocalToGlobalMapping` provided to it with `MatSetLocalToGlobalMapping()`.
10685:   Matrices obtained with `DMCreateMatrix()` generally already have the local to global mapping provided.

10687: .seealso: [](ch_matrices), `Mat`, `MatRestoreLocalSubMatrix()`, `MatCreateLocalRef()`, `MatSetLocalToGlobalMapping()`
10688: @*/
10689: PetscErrorCode MatGetLocalSubMatrix(Mat mat, IS isrow, IS iscol, Mat *submat)
10690: {
10691:   PetscFunctionBegin;
10695:   PetscCheckSameComm(isrow, 2, iscol, 3);
10696:   PetscAssertPointer(submat, 4);
10697:   PetscCheck(mat->rmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Matrix must have local to global mapping provided before this call");

10699:   if (mat->ops->getlocalsubmatrix) {
10700:     PetscUseTypeMethod(mat, getlocalsubmatrix, isrow, iscol, submat);
10701:   } else {
10702:     PetscCall(MatCreateLocalRef(mat, isrow, iscol, submat));
10703:   }
10704:   PetscFunctionReturn(PETSC_SUCCESS);
10705: }

10707: /*@
10708:   MatRestoreLocalSubMatrix - Restores a reference to a submatrix specified in local numbering obtained with `MatGetLocalSubMatrix()`

10710:   Not Collective

10712:   Input Parameters:
10713: + mat    - matrix to extract local submatrix from
10714: . isrow  - local row indices for submatrix
10715: . iscol  - local column indices for submatrix
10716: - submat - the submatrix

10718:   Level: intermediate

10720: .seealso: [](ch_matrices), `Mat`, `MatGetLocalSubMatrix()`
10721: @*/
10722: PetscErrorCode MatRestoreLocalSubMatrix(Mat mat, IS isrow, IS iscol, Mat *submat)
10723: {
10724:   PetscFunctionBegin;
10728:   PetscCheckSameComm(isrow, 2, iscol, 3);
10729:   PetscAssertPointer(submat, 4);

10732:   if (mat->ops->restorelocalsubmatrix) {
10733:     PetscUseTypeMethod(mat, restorelocalsubmatrix, isrow, iscol, submat);
10734:   } else {
10735:     PetscCall(MatDestroy(submat));
10736:   }
10737:   *submat = NULL;
10738:   PetscFunctionReturn(PETSC_SUCCESS);
10739: }

10741: /*@
10742:   MatFindZeroDiagonals - Finds all the rows of a matrix that have zero or no diagonal entry in the matrix

10744:   Collective

10746:   Input Parameter:
10747: . mat - the matrix

10749:   Output Parameter:
10750: . is - if any rows have zero diagonals this contains the list of them

10752:   Level: developer

10754: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMultAdd()`, `MatMultTransposeAdd()`
10755: @*/
10756: PetscErrorCode MatFindZeroDiagonals(Mat mat, IS *is)
10757: {
10758:   PetscFunctionBegin;
10761:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
10762:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");

10764:   if (!mat->ops->findzerodiagonals) {
10765:     Vec                diag;
10766:     const PetscScalar *a;
10767:     PetscInt          *rows;
10768:     PetscInt           rStart, rEnd, r, nrow = 0;

10770:     PetscCall(MatCreateVecs(mat, &diag, NULL));
10771:     PetscCall(MatGetDiagonal(mat, diag));
10772:     PetscCall(MatGetOwnershipRange(mat, &rStart, &rEnd));
10773:     PetscCall(VecGetArrayRead(diag, &a));
10774:     for (r = 0; r < rEnd - rStart; ++r)
10775:       if (a[r] == 0.0) ++nrow;
10776:     PetscCall(PetscMalloc1(nrow, &rows));
10777:     nrow = 0;
10778:     for (r = 0; r < rEnd - rStart; ++r)
10779:       if (a[r] == 0.0) rows[nrow++] = r + rStart;
10780:     PetscCall(VecRestoreArrayRead(diag, &a));
10781:     PetscCall(VecDestroy(&diag));
10782:     PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)mat), nrow, rows, PETSC_OWN_POINTER, is));
10783:   } else {
10784:     PetscUseTypeMethod(mat, findzerodiagonals, is);
10785:   }
10786:   PetscFunctionReturn(PETSC_SUCCESS);
10787: }

10789: /*@
10790:   MatFindOffBlockDiagonalEntries - Finds all the rows of a matrix that have entries outside of the main diagonal block (defined by the matrix block size)

10792:   Collective

10794:   Input Parameter:
10795: . mat - the matrix

10797:   Output Parameter:
10798: . is - contains the list of rows with off block diagonal entries

10800:   Level: developer

10802: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMultAdd()`, `MatMultTransposeAdd()`
10803: @*/
10804: PetscErrorCode MatFindOffBlockDiagonalEntries(Mat mat, IS *is)
10805: {
10806:   PetscFunctionBegin;
10809:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
10810:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");

10812:   PetscUseTypeMethod(mat, findoffblockdiagonalentries, is);
10813:   PetscFunctionReturn(PETSC_SUCCESS);
10814: }

10816: /*@C
10817:   MatInvertBlockDiagonal - Inverts the block diagonal entries.

10819:   Collective; No Fortran Support

10821:   Input Parameter:
10822: . mat - the matrix

10824:   Output Parameter:
10825: . values - the block inverses in column major order (FORTRAN-like)

10827:   Level: advanced

10829:   Notes:
10830:   The size of the blocks is determined by the block size of the matrix.

10832:   The blocks never overlap between two MPI processes, use `MatInvertVariableBlockEnvelope()` for that case

10834:   The blocks all have the same size, use `MatInvertVariableBlockDiagonal()` for variable block size

10836: .seealso: [](ch_matrices), `Mat`, `MatInvertVariableBlockEnvelope()`, `MatInvertBlockDiagonalMat()`
10837: @*/
10838: PetscErrorCode MatInvertBlockDiagonal(Mat mat, const PetscScalar *values[])
10839: {
10840:   PetscFunctionBegin;
10842:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
10843:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
10844:   PetscUseTypeMethod(mat, invertblockdiagonal, values);
10845:   PetscFunctionReturn(PETSC_SUCCESS);
10846: }

10848: /*@
10849:   MatInvertVariableBlockDiagonal - Inverts the point block diagonal entries.

10851:   Collective; No Fortran Support

10853:   Input Parameters:
10854: + mat     - the matrix
10855: . nblocks - the number of blocks on the process, set with `MatSetVariableBlockSizes()`
10856: - bsizes  - the size of each block on the process, set with `MatSetVariableBlockSizes()`

10858:   Output Parameter:
10859: . values - the block inverses in column major order (FORTRAN-like)

10861:   Level: advanced

10863:   Notes:
10864:   Use `MatInvertBlockDiagonal()` if all blocks have the same size

10866:   The blocks never overlap between two MPI processes, use `MatInvertVariableBlockEnvelope()` for that case

10868: .seealso: [](ch_matrices), `Mat`, `MatInvertBlockDiagonal()`, `MatSetVariableBlockSizes()`, `MatInvertVariableBlockEnvelope()`
10869: @*/
10870: PetscErrorCode MatInvertVariableBlockDiagonal(Mat mat, PetscInt nblocks, const PetscInt bsizes[], PetscScalar values[])
10871: {
10872:   PetscFunctionBegin;
10874:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
10875:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
10876:   PetscUseTypeMethod(mat, invertvariableblockdiagonal, nblocks, bsizes, values);
10877:   PetscFunctionReturn(PETSC_SUCCESS);
10878: }

10880: /*@
10881:   MatInvertBlockDiagonalMat - set the values of matrix C to be the inverted block diagonal of matrix A

10883:   Collective

10885:   Input Parameters:
10886: + A - the matrix
10887: - C - matrix with inverted block diagonal of `A`.  This matrix should be created and may have its type set.

10889:   Level: advanced

10891:   Note:
10892:   The blocksize of the matrix is used to determine the blocks on the diagonal of `C`

10894: .seealso: [](ch_matrices), `Mat`, `MatInvertBlockDiagonal()`
10895: @*/
10896: PetscErrorCode MatInvertBlockDiagonalMat(Mat A, Mat C)
10897: {
10898:   const PetscScalar *vals;
10899:   PetscInt          *dnnz;
10900:   PetscInt           m, rstart, rend, bs, i, j;

10902:   PetscFunctionBegin;
10903:   PetscCall(MatInvertBlockDiagonal(A, &vals));
10904:   PetscCall(MatGetBlockSize(A, &bs));
10905:   PetscCall(MatGetLocalSize(A, &m, NULL));
10906:   PetscCall(MatSetLayouts(C, A->rmap, A->cmap));
10907:   PetscCall(PetscMalloc1(m / bs, &dnnz));
10908:   for (j = 0; j < m / bs; j++) dnnz[j] = 1;
10909:   PetscCall(MatXAIJSetPreallocation(C, bs, dnnz, NULL, NULL, NULL));
10910:   PetscCall(PetscFree(dnnz));
10911:   PetscCall(MatGetOwnershipRange(C, &rstart, &rend));
10912:   PetscCall(MatSetOption(C, MAT_ROW_ORIENTED, PETSC_FALSE));
10913:   for (i = rstart / bs; i < rend / bs; i++) PetscCall(MatSetValuesBlocked(C, 1, &i, 1, &i, &vals[(i - rstart / bs) * bs * bs], INSERT_VALUES));
10914:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
10915:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
10916:   PetscCall(MatSetOption(C, MAT_ROW_ORIENTED, PETSC_TRUE));
10917:   PetscFunctionReturn(PETSC_SUCCESS);
10918: }

10920: /*@
10921:   MatTransposeColoringDestroy - Destroys a coloring context for matrix product $C = A*B^T$ that was created
10922:   via `MatTransposeColoringCreate()`.

10924:   Collective

10926:   Input Parameter:
10927: . c - coloring context

10929:   Level: intermediate

10931: .seealso: [](ch_matrices), `Mat`, `MatTransposeColoringCreate()`
10932: @*/
10933: PetscErrorCode MatTransposeColoringDestroy(MatTransposeColoring *c)
10934: {
10935:   MatTransposeColoring matcolor = *c;

10937:   PetscFunctionBegin;
10938:   if (!matcolor) PetscFunctionReturn(PETSC_SUCCESS);
10939:   if (--((PetscObject)matcolor)->refct > 0) {
10940:     matcolor = NULL;
10941:     PetscFunctionReturn(PETSC_SUCCESS);
10942:   }

10944:   PetscCall(PetscFree3(matcolor->ncolumns, matcolor->nrows, matcolor->colorforrow));
10945:   PetscCall(PetscFree(matcolor->rows));
10946:   PetscCall(PetscFree(matcolor->den2sp));
10947:   PetscCall(PetscFree(matcolor->colorforcol));
10948:   PetscCall(PetscFree(matcolor->columns));
10949:   if (matcolor->brows > 0) PetscCall(PetscFree(matcolor->lstart));
10950:   PetscCall(PetscHeaderDestroy(c));
10951:   PetscFunctionReturn(PETSC_SUCCESS);
10952: }

10954: /*@
10955:   MatTransColoringApplySpToDen - Given a symbolic matrix product $C = A*B^T$ for which
10956:   a `MatTransposeColoring` context has been created, computes a dense $B^T$ by applying
10957:   `MatTransposeColoring` to sparse `B`.

10959:   Collective

10961:   Input Parameters:
10962: + coloring - coloring context created with `MatTransposeColoringCreate()`
10963: - B        - sparse matrix

10965:   Output Parameter:
10966: . Btdense - dense matrix $B^T$

10968:   Level: developer

10970:   Note:
10971:   These are used internally for some implementations of `MatRARt()`

10973: .seealso: [](ch_matrices), `Mat`, `MatTransposeColoringCreate()`, `MatTransposeColoringDestroy()`, `MatTransColoringApplyDenToSp()`
10974: @*/
10975: PetscErrorCode MatTransColoringApplySpToDen(MatTransposeColoring coloring, Mat B, Mat Btdense)
10976: {
10977:   PetscFunctionBegin;

10982:   PetscCall((*B->ops->transcoloringapplysptoden)(coloring, B, Btdense));
10983:   PetscFunctionReturn(PETSC_SUCCESS);
10984: }

10986: /*@
10987:   MatTransColoringApplyDenToSp - Given a symbolic matrix product $C_{sp} = A*B^T$ for which
10988:   a `MatTransposeColoring` context has been created and a dense matrix $C_{den} = A*B^T_{dense}$
10989:   in which `B^T_{dens}` is obtained from `MatTransColoringApplySpToDen()`, recover sparse matrix
10990:   $C_{sp}$ from $C_{den}$.

10992:   Collective

10994:   Input Parameters:
10995: + matcoloring - coloring context created with `MatTransposeColoringCreate()`
10996: - Cden        - matrix product of a sparse matrix and a dense matrix Btdense

10998:   Output Parameter:
10999: . Csp - sparse matrix

11001:   Level: developer

11003:   Note:
11004:   These are used internally for some implementations of `MatRARt()`

11006: .seealso: [](ch_matrices), `Mat`, `MatTransposeColoringCreate()`, `MatTransposeColoringDestroy()`, `MatTransColoringApplySpToDen()`
11007: @*/
11008: PetscErrorCode MatTransColoringApplyDenToSp(MatTransposeColoring matcoloring, Mat Cden, Mat Csp)
11009: {
11010:   PetscFunctionBegin;

11015:   PetscCall((*Csp->ops->transcoloringapplydentosp)(matcoloring, Cden, Csp));
11016:   PetscCall(MatAssemblyBegin(Csp, MAT_FINAL_ASSEMBLY));
11017:   PetscCall(MatAssemblyEnd(Csp, MAT_FINAL_ASSEMBLY));
11018:   PetscFunctionReturn(PETSC_SUCCESS);
11019: }

11021: /*@
11022:   MatTransposeColoringCreate - Creates a matrix coloring context for the matrix product $C = A*B^T$.

11024:   Collective

11026:   Input Parameters:
11027: + mat        - the matrix product C
11028: - iscoloring - the coloring of the matrix; usually obtained with `MatColoringCreate()` or `DMCreateColoring()`

11030:   Output Parameter:
11031: . color - the new coloring context

11033:   Level: intermediate

11035: .seealso: [](ch_matrices), `Mat`, `MatTransposeColoringDestroy()`, `MatTransColoringApplySpToDen()`,
11036:           `MatTransColoringApplyDenToSp()`
11037: @*/
11038: PetscErrorCode MatTransposeColoringCreate(Mat mat, ISColoring iscoloring, MatTransposeColoring *color)
11039: {
11040:   MatTransposeColoring c;
11041:   MPI_Comm             comm;

11043:   PetscFunctionBegin;
11044:   PetscAssertPointer(color, 3);

11046:   PetscCall(PetscLogEventBegin(MAT_TransposeColoringCreate, mat, 0, 0, 0));
11047:   PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
11048:   PetscCall(PetscHeaderCreate(c, MAT_TRANSPOSECOLORING_CLASSID, "MatTransposeColoring", "Matrix product C=A*B^T via coloring", "Mat", comm, MatTransposeColoringDestroy, NULL));
11049:   c->ctype = iscoloring->ctype;
11050:   PetscUseTypeMethod(mat, transposecoloringcreate, iscoloring, c);
11051:   *color = c;
11052:   PetscCall(PetscLogEventEnd(MAT_TransposeColoringCreate, mat, 0, 0, 0));
11053:   PetscFunctionReturn(PETSC_SUCCESS);
11054: }

11056: /*@
11057:   MatGetNonzeroState - Returns a 64-bit integer representing the current state of nonzeros in the matrix. If the
11058:   matrix has had new nonzero locations added to (or removed from) the matrix since the previous call, the value will be larger.

11060:   Not Collective

11062:   Input Parameter:
11063: . mat - the matrix

11065:   Output Parameter:
11066: . state - the current state

11068:   Level: intermediate

11070:   Notes:
11071:   You can only compare states from two different calls to the SAME matrix, you cannot compare calls between
11072:   different matrices

11074:   Use `PetscObjectStateGet()` to check for changes to the numerical values in a matrix

11076:   Use the result of `PetscObjectGetId()` to compare if a previously checked matrix is the same as the current matrix, do not compare object pointers.

11078: .seealso: [](ch_matrices), `Mat`, `PetscObjectStateGet()`, `PetscObjectGetId()`
11079: @*/
11080: PetscErrorCode MatGetNonzeroState(Mat mat, PetscObjectState *state)
11081: {
11082:   PetscFunctionBegin;
11084:   *state = mat->nonzerostate;
11085:   PetscFunctionReturn(PETSC_SUCCESS);
11086: }

11088: /*@
11089:   MatCreateMPIMatConcatenateSeqMat - Creates a single large PETSc matrix by concatenating sequential
11090:   matrices from each processor

11092:   Collective

11094:   Input Parameters:
11095: + comm   - the communicators the parallel matrix will live on
11096: . seqmat - the input sequential matrices
11097: . n      - number of local columns (or `PETSC_DECIDE`)
11098: - reuse  - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

11100:   Output Parameter:
11101: . mpimat - the parallel matrix generated

11103:   Level: developer

11105:   Note:
11106:   The number of columns of the matrix in EACH processor MUST be the same.

11108: .seealso: [](ch_matrices), `Mat`
11109: @*/
11110: PetscErrorCode MatCreateMPIMatConcatenateSeqMat(MPI_Comm comm, Mat seqmat, PetscInt n, MatReuse reuse, Mat *mpimat)
11111: {
11112:   PetscMPIInt size;

11114:   PetscFunctionBegin;
11115:   PetscCallMPI(MPI_Comm_size(comm, &size));
11116:   if (size == 1) {
11117:     if (reuse == MAT_INITIAL_MATRIX) {
11118:       PetscCall(MatDuplicate(seqmat, MAT_COPY_VALUES, mpimat));
11119:     } else {
11120:       PetscCall(MatCopy(seqmat, *mpimat, SAME_NONZERO_PATTERN));
11121:     }
11122:     PetscFunctionReturn(PETSC_SUCCESS);
11123:   }

11125:   PetscCheck(reuse != MAT_REUSE_MATRIX || seqmat != *mpimat, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MAT_REUSE_MATRIX means reuse the matrix passed in as the final argument, not the original matrix");

11127:   PetscCall(PetscLogEventBegin(MAT_Merge, seqmat, 0, 0, 0));
11128:   PetscCall((*seqmat->ops->creatempimatconcatenateseqmat)(comm, seqmat, n, reuse, mpimat));
11129:   PetscCall(PetscLogEventEnd(MAT_Merge, seqmat, 0, 0, 0));
11130:   PetscFunctionReturn(PETSC_SUCCESS);
11131: }

11133: /*@
11134:   MatSubdomainsCreateCoalesce - Creates index subdomains by coalescing adjacent MPI processes' ownership ranges.

11136:   Collective

11138:   Input Parameters:
11139: + A - the matrix to create subdomains from
11140: - N - requested number of subdomains

11142:   Output Parameters:
11143: + n   - number of subdomains resulting on this MPI process
11144: - iss - `IS` list with indices of subdomains on this MPI process

11146:   Level: advanced

11148:   Note:
11149:   The number of subdomains must be smaller than the communicator size

11151: .seealso: [](ch_matrices), `Mat`, `IS`
11152: @*/
11153: PetscErrorCode MatSubdomainsCreateCoalesce(Mat A, PetscInt N, PetscInt *n, IS *iss[])
11154: {
11155:   MPI_Comm    comm, subcomm;
11156:   PetscMPIInt size, rank, color;
11157:   PetscInt    rstart, rend, k;

11159:   PetscFunctionBegin;
11160:   PetscCall(PetscObjectGetComm((PetscObject)A, &comm));
11161:   PetscCallMPI(MPI_Comm_size(comm, &size));
11162:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
11163:   PetscCheck(N >= 1 && N < (PetscInt)size, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "number of subdomains must be > 0 and < %d, got N = %" PetscInt_FMT, size, N);
11164:   *n    = 1;
11165:   k     = ((PetscInt)size) / N + ((PetscInt)size % N > 0); /* There are up to k ranks to a color */
11166:   color = rank / k;
11167:   PetscCallMPI(MPI_Comm_split(comm, color, rank, &subcomm));
11168:   PetscCall(PetscMalloc1(1, iss));
11169:   PetscCall(MatGetOwnershipRange(A, &rstart, &rend));
11170:   PetscCall(ISCreateStride(subcomm, rend - rstart, rstart, 1, iss[0]));
11171:   PetscCallMPI(MPI_Comm_free(&subcomm));
11172:   PetscFunctionReturn(PETSC_SUCCESS);
11173: }

11175: /*@
11176:   MatGalerkin - Constructs the coarse grid problem matrix via Galerkin projection.

11178:   If the interpolation and restriction operators are the same, uses `MatPtAP()`.
11179:   If they are not the same, uses `MatMatMatMult()`.

11181:   Once the coarse grid problem is constructed, correct for interpolation operators
11182:   that are not of full rank, which can legitimately happen in the case of non-nested
11183:   geometric multigrid.

11185:   Input Parameters:
11186: + restrct     - restriction operator
11187: . dA          - fine grid matrix
11188: . interpolate - interpolation operator
11189: . reuse       - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
11190: - fill        - expected fill, use `PETSC_DETERMINE` or `PETSC_DETERMINE` if you do not have a good estimate

11192:   Output Parameter:
11193: . A - the Galerkin coarse matrix

11195:   Options Database Key:
11196: . -pc_mg_galerkin <both,pmat,mat,none> - for what matrices the Galerkin process should be used

11198:   Level: developer

11200:   Note:
11201:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

11203: .seealso: [](ch_matrices), `Mat`, `MatPtAP()`, `MatMatMatMult()`
11204: @*/
11205: PetscErrorCode MatGalerkin(Mat restrct, Mat dA, Mat interpolate, MatReuse reuse, PetscReal fill, Mat *A)
11206: {
11207:   IS  zerorows;
11208:   Vec diag;

11210:   PetscFunctionBegin;
11211:   PetscCheck(reuse != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Inplace product not supported");
11212:   /* Construct the coarse grid matrix */
11213:   if (interpolate == restrct) {
11214:     PetscCall(MatPtAP(dA, interpolate, reuse, fill, A));
11215:   } else {
11216:     PetscCall(MatMatMatMult(restrct, dA, interpolate, reuse, fill, A));
11217:   }

11219:   /* If the interpolation matrix is not of full rank, A will have zero rows.
11220:      This can legitimately happen in the case of non-nested geometric multigrid.
11221:      In that event, we set the rows of the matrix to the rows of the identity,
11222:      ignoring the equations (as the RHS will also be zero). */

11224:   PetscCall(MatFindZeroRows(*A, &zerorows));

11226:   if (zerorows != NULL) { /* if there are any zero rows */
11227:     PetscCall(MatCreateVecs(*A, &diag, NULL));
11228:     PetscCall(MatGetDiagonal(*A, diag));
11229:     PetscCall(VecISSet(diag, zerorows, 1.0));
11230:     PetscCall(MatDiagonalSet(*A, diag, INSERT_VALUES));
11231:     PetscCall(VecDestroy(&diag));
11232:     PetscCall(ISDestroy(&zerorows));
11233:   }
11234:   PetscFunctionReturn(PETSC_SUCCESS);
11235: }

11237: /*@C
11238:   MatSetOperation - Allows user to set a matrix operation for any matrix type

11240:   Logically Collective

11242:   Input Parameters:
11243: + mat - the matrix
11244: . op  - the name of the operation
11245: - f   - the function that provides the operation

11247:   Level: developer

11249:   Example Usage:
11250: .vb
11251:   extern PetscErrorCode usermult(Mat, Vec, Vec);

11253:   PetscCall(MatCreateXXX(comm, ..., &A));
11254:   PetscCall(MatSetOperation(A, MATOP_MULT, (PetscVoidFn *)usermult));
11255: .ve

11257:   Notes:
11258:   See the file `include/petscmat.h` for a complete list of matrix
11259:   operations, which all have the form MATOP_<OPERATION>, where
11260:   <OPERATION> is the name (in all capital letters) of the
11261:   user interface routine (e.g., `MatMult()` -> `MATOP_MULT`).

11263:   All user-provided functions (except for `MATOP_DESTROY`) should have the same calling
11264:   sequence as the usual matrix interface routines, since they
11265:   are intended to be accessed via the usual matrix interface
11266:   routines, e.g.,
11267: .vb
11268:   MatMult(Mat, Vec, Vec) -> usermult(Mat, Vec, Vec)
11269: .ve

11271:   In particular each function MUST return `PETSC_SUCCESS` on success and
11272:   nonzero on failure.

11274:   This routine is distinct from `MatShellSetOperation()` in that it can be called on any matrix type.

11276: .seealso: [](ch_matrices), `Mat`, `MatGetOperation()`, `MatCreateShell()`, `MatShellSetContext()`, `MatShellSetOperation()`
11277: @*/
11278: PetscErrorCode MatSetOperation(Mat mat, MatOperation op, void (*f)(void))
11279: {
11280:   PetscFunctionBegin;
11282:   if (op == MATOP_VIEW && !mat->ops->viewnative && f != (void (*)(void))mat->ops->view) mat->ops->viewnative = mat->ops->view;
11283:   (((void (**)(void))mat->ops)[op]) = f;
11284:   PetscFunctionReturn(PETSC_SUCCESS);
11285: }

11287: /*@C
11288:   MatGetOperation - Gets a matrix operation for any matrix type.

11290:   Not Collective

11292:   Input Parameters:
11293: + mat - the matrix
11294: - op  - the name of the operation

11296:   Output Parameter:
11297: . f - the function that provides the operation

11299:   Level: developer

11301:   Example Usage:
11302: .vb
11303:   PetscErrorCode (*usermult)(Mat, Vec, Vec);

11305:   MatGetOperation(A, MATOP_MULT, (void (**)(void))&usermult);
11306: .ve

11308:   Notes:
11309:   See the file include/petscmat.h for a complete list of matrix
11310:   operations, which all have the form MATOP_<OPERATION>, where
11311:   <OPERATION> is the name (in all capital letters) of the
11312:   user interface routine (e.g., `MatMult()` -> `MATOP_MULT`).

11314:   This routine is distinct from `MatShellGetOperation()` in that it can be called on any matrix type.

11316: .seealso: [](ch_matrices), `Mat`, `MatSetOperation()`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`
11317: @*/
11318: PetscErrorCode MatGetOperation(Mat mat, MatOperation op, void (**f)(void))
11319: {
11320:   PetscFunctionBegin;
11322:   *f = (((void (**)(void))mat->ops)[op]);
11323:   PetscFunctionReturn(PETSC_SUCCESS);
11324: }

11326: /*@
11327:   MatHasOperation - Determines whether the given matrix supports the particular operation.

11329:   Not Collective

11331:   Input Parameters:
11332: + mat - the matrix
11333: - op  - the operation, for example, `MATOP_GET_DIAGONAL`

11335:   Output Parameter:
11336: . has - either `PETSC_TRUE` or `PETSC_FALSE`

11338:   Level: advanced

11340:   Note:
11341:   See `MatSetOperation()` for additional discussion on naming convention and usage of `op`.

11343: .seealso: [](ch_matrices), `Mat`, `MatCreateShell()`, `MatGetOperation()`, `MatSetOperation()`
11344: @*/
11345: PetscErrorCode MatHasOperation(Mat mat, MatOperation op, PetscBool *has)
11346: {
11347:   PetscFunctionBegin;
11349:   PetscAssertPointer(has, 3);
11350:   if (mat->ops->hasoperation) {
11351:     PetscUseTypeMethod(mat, hasoperation, op, has);
11352:   } else {
11353:     if (((void **)mat->ops)[op]) *has = PETSC_TRUE;
11354:     else {
11355:       *has = PETSC_FALSE;
11356:       if (op == MATOP_CREATE_SUBMATRIX) {
11357:         PetscMPIInt size;

11359:         PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size));
11360:         if (size == 1) PetscCall(MatHasOperation(mat, MATOP_CREATE_SUBMATRICES, has));
11361:       }
11362:     }
11363:   }
11364:   PetscFunctionReturn(PETSC_SUCCESS);
11365: }

11367: /*@
11368:   MatHasCongruentLayouts - Determines whether the rows and columns layouts of the matrix are congruent

11370:   Collective

11372:   Input Parameter:
11373: . mat - the matrix

11375:   Output Parameter:
11376: . cong - either `PETSC_TRUE` or `PETSC_FALSE`

11378:   Level: beginner

11380: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatSetSizes()`, `PetscLayout`
11381: @*/
11382: PetscErrorCode MatHasCongruentLayouts(Mat mat, PetscBool *cong)
11383: {
11384:   PetscFunctionBegin;
11387:   PetscAssertPointer(cong, 2);
11388:   if (!mat->rmap || !mat->cmap) {
11389:     *cong = mat->rmap == mat->cmap ? PETSC_TRUE : PETSC_FALSE;
11390:     PetscFunctionReturn(PETSC_SUCCESS);
11391:   }
11392:   if (mat->congruentlayouts == PETSC_DECIDE) { /* first time we compare rows and cols layouts */
11393:     PetscCall(PetscLayoutSetUp(mat->rmap));
11394:     PetscCall(PetscLayoutSetUp(mat->cmap));
11395:     PetscCall(PetscLayoutCompare(mat->rmap, mat->cmap, cong));
11396:     if (*cong) mat->congruentlayouts = 1;
11397:     else mat->congruentlayouts = 0;
11398:   } else *cong = mat->congruentlayouts ? PETSC_TRUE : PETSC_FALSE;
11399:   PetscFunctionReturn(PETSC_SUCCESS);
11400: }

11402: PetscErrorCode MatSetInf(Mat A)
11403: {
11404:   PetscFunctionBegin;
11405:   PetscUseTypeMethod(A, setinf);
11406:   PetscFunctionReturn(PETSC_SUCCESS);
11407: }

11409: /*@
11410:   MatCreateGraph - create a scalar matrix (that is a matrix with one vertex for each block vertex in the original matrix), for use in graph algorithms
11411:   and possibly removes small values from the graph structure.

11413:   Collective

11415:   Input Parameters:
11416: + A       - the matrix
11417: . sym     - `PETSC_TRUE` indicates that the graph should be symmetrized
11418: . scale   - `PETSC_TRUE` indicates that the graph edge weights should be symmetrically scaled with the diagonal entry
11419: . filter  - filter value - < 0: does nothing; == 0: removes only 0.0 entries; otherwise: removes entries with abs(entries) <= value
11420: . num_idx - size of 'index' array
11421: - index   - array of block indices to use for graph strength of connection weight

11423:   Output Parameter:
11424: . graph - the resulting graph

11426:   Level: advanced

11428: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `PCGAMG`
11429: @*/
11430: PetscErrorCode MatCreateGraph(Mat A, PetscBool sym, PetscBool scale, PetscReal filter, PetscInt num_idx, PetscInt index[], Mat *graph)
11431: {
11432:   PetscFunctionBegin;
11436:   PetscAssertPointer(graph, 7);
11437:   PetscCall(PetscLogEventBegin(MAT_CreateGraph, A, 0, 0, 0));
11438:   PetscUseTypeMethod(A, creategraph, sym, scale, filter, num_idx, index, graph);
11439:   PetscCall(PetscLogEventEnd(MAT_CreateGraph, A, 0, 0, 0));
11440:   PetscFunctionReturn(PETSC_SUCCESS);
11441: }

11443: /*@
11444:   MatEliminateZeros - eliminate the nondiagonal zero entries in place from the nonzero structure of a sparse `Mat` in place,
11445:   meaning the same memory is used for the matrix, and no new memory is allocated.

11447:   Collective

11449:   Input Parameters:
11450: + A    - the matrix
11451: - keep - if for a given row of `A`, the diagonal coefficient is zero, indicates whether it should be left in the structure or eliminated as well

11453:   Level: intermediate

11455:   Developer Note:
11456:   The entries in the sparse matrix data structure are shifted to fill in the unneeded locations in the data. Thus the end
11457:   of the arrays in the data structure are unneeded.

11459: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatCreateGraph()`, `MatFilter()`
11460: @*/
11461: PetscErrorCode MatEliminateZeros(Mat A, PetscBool keep)
11462: {
11463:   PetscFunctionBegin;
11465:   PetscUseTypeMethod(A, eliminatezeros, keep);
11466:   PetscFunctionReturn(PETSC_SUCCESS);
11467: }