# Changes: 3.0.0

```{rubric} General:
```

- Changed the MATLAB engine portion of the MATLAB configure code to
  require a separate flag --with-matlab-engine
- Changed the Socket viewer to be the same as the binary viewer
  except for its creation
- Changed the MATLAB Socket code to work the same as the Matlab
  binary reader except for its creation
- You can now replace the PetscVFPrintf() function pointer to
  redirect all stdout/stderr output in Microsoft Windows for example.
- Removed MPICCommToFortran() and MPIFortranCommToC() since
  MPI_Comm_c2f() and f2c() are now always available.
- PetscOptionsInsertFile() now takes a MPI_Comm as the first
  argument and a final flag argument indicating if the file  MUST be
  located. It is also changed to be more scalable, only the 0th
  process opens it and broadcasts the input to the other processes.
- Added PetscObjectIncrementTabLevel() to allow proper indenting of
  monitor output for embedded solvers for multigrid levels, for
  block Jacobi, for SNES inside TS and KSP inside SNES etc.

```{rubric} Logging:
```

- The int stage used in the PetscLogStageXXX() routines is now a
  PetscLogStage
- PetscLogEventRegister() and PetscLogStageRegister() now return the
  result in the final argument instead of the first
- PetscLogClassRegister() is changed to PetscClassIdRegister() and
  returns the classid in the final argument, not the first
- PetscEvent is now PetscLogEvent

```{rubric} config/configure.py:
```

- Changed location of base makefiles to conf from bmake/common
- Changed location of generated base makefiles to \$PETSC_ARCH/conf
  instead of bmake/\$PETSC_ARCH
- Changed location of generated include files to \$PETSC_ARCH/include
- Changed location of generated libraries (including from external
  packages) to \$PETSC_ARCH/lib
- You will need to change include \$\{PETSC_DIR}/bmake/common/base to
  \$\{PETSC_DIR}/conf/base

```{rubric} IS:
```

- ISPartitioningCount() now takes an additional argument, the length
  of the count array (that is the number of partitions).

```{rubric} Vec:
```

- Added logical argument to VecSetOption() to toggle option in
  either way
- The PetscMap inside the Vec object is now allocated and reference
  counted and shared between vectors and matrices, this will
  decrease memory usage on systems with a large size.

```{rubric} VecScatter:
```

```{rubric} Mat:
```

- MatSetOption() now takes a final PetscTruth flag to toggle the
  option. The redundant options like MAT_NO_SYMMETRIC are removed
- The MatSetOption() options MAT_ROWS_SORTED, MAT_COLUMNS_SORTED are
  no longer needed and are removed.
- MatConvert() now uses the matrix prefix when using option
  -matconvert_type.
- The bdiag matrix formats have been removed
- MatTranspose() now takes a new second argument MatReuse; also to
  do an inplace transpose use MAT_REUSE_MATRIX and pass the address
  of the first argument as the third argument (you can no longer
  pass 0).
- MATPLAPACK is removed; instead so long as PETSc is
  config/configure.py with --download-plapack the MATMPIDENSE matrix
  will automatically use the parallel plapack solvers
- The "parallel direct solver" matrix types like
  MATAIJSPOOLES are ALL gone. Now you use
  -pc_factor_mat_solver_package
  spooles etc or PCFactorSetMatSolverPackage() or if working
  directly with
  matrices, MatGetFactor(A,MATSPOOLES,...)
- Removed MatFDColoringSetRecompute(), now use
  MatFDSetFrequency(mat,-2) to have Jacobian computed at next Newton
  step but never again.
- Removed MatFDColoringSet/GetFrequency() and -mat_fd_coloring_freq
  since you can now use SNESSetLagJacobian() or -snes_lag_jacobian
- The PetscMap inside the Mat object is now allocated and reference
  counted and shared between vectors and matrices, this will
  decrease memory usage on systems with a large size.
- The first argument to MatXXXFactorSymbolic/Numeric() is now the
  factored matrix
- The fields global_rows,global_columns,local_rows,local_columns
  have been removed from the MatGetInfo() data. User MatGetSize(),
  MatGetLocalSize() to get that data

```{rubric} PC:
```

- PCHasApplyTranspose() was renamed to PCApplyTransposeExists().
- Added much faster matrix converter to use hypre preconditioners
  for PETSc AIJ matrices
- ILU preconditioner now defaults to use shift to prevent zero pivot
- ICC preconditioner now defaults to use Manteuffel shift to force
  positive definiteness
- Added -pc_factor_shift_in_blocks and PCFactorSetShiftInBlocks()
  made default for ILU
- PCApplyRichardson() now returns two additional arguments, the
  number of iterations performed and the reason it finished.

```{rubric} KSP:
```

- KSPSetConvergenceTest() now takes an optional final argument,
  destroy() that will be called to destroy the context passed in as
  the second to last argument
- KSPDefaultConverged() now has a KSPDefaultConvergedCreate() and
  KSPDefaultConvergedDestroy() that creates the default context to
  be passed KSPSetConvergenceTest() and the destroy to be passed in.
- Added KSPIBCGS a variant of Bi-CG-stab that has only 1
  synchronization point rather than 3 in the usual.

```{rubric} SNES:
```

- SNESSetRhs() and SNESSetSolution() were removed. Use instead
  SNESSolve(snes, b, x) to pass right-hand side (optional, can be
  PETSC_NULL) and solution (required).
- SNES now takes ownership of user-provided vector for right hand
  side and solution passed to SNESSolve(), and until the next
  SNESSolve() is called.
- SNES now takes ownership of user-provided vector for function
  evalutation passed to SNESSetFunction(), thus this vector can be
  safely destroyed after this call.
- SNESConverged_LS() and SNESConverged_LS() were removed. Use
  SNESDefaultConverged() or SNESSkipConverged() as convergence test.
- Option -snes_convergence_test was added, accepting values
  default|short, for setting SNESDefaultConverged() or
  SNESSkipConverged() as convergence test.
- Option -snes_no_convergence_test was removed. Use instead
  "-snes_convergence_test skip".
- Do not use the error PETSC_ERR_ARG_DOMAIN within your
  FormFunction() rather call SNESSetFunctionDomainError.
- The line search functions now take an additional argument xnorm.
- SNESSetConvergenceTest() takes another optional argument
  PetscErrorCode (*destroy)(void*) that will be called with
  SNESDestroy() to destroy the context.
- Added SNESSetLagPreconditioner(), -snes_lag_preconditioner,
  SNESGetLagPreconditioner()
- Added SNESSetLagJacobian(), -snes_lag_jacobian,
  SNESGetLagJacobian()

```{rubric} TS:
```

```{rubric} DA:
```

- Added DAGetNeighbors()
- Added DAGetOwnershipRanges()

```{rubric} DMMG:
```

- Added DMMGSetFromOptions(), this can only be used in conjunction
  with DMMGSetSNES(). You should call this sometime after
  DMMGSetSNES() is called, otherwise the SNES/KSPSetFromOptions()
  does not get called.
- Removed -dmmg_snes_monitor since now -snes_monitor and
  -snes_monitor_short will now do the proper indenting so this is no
  longer needed
- Removed -dmmg_ksp_monitor since now -ksp_monitor\[\_short) and
  -mg_levels_ksp_monitor\[\_short) etc will handle the proper
  indenting.
- Removed -dmmg_jacobian_period since you can use -snes_lag_jacobian

```{rubric} PetscViewer:
```

- added PETSC_VIEWER_STDOUT\_(comm) for Fortran
- binary viewer now supports MPI IO for Vec loading and storing, use
  -viewer_binary_mpiio or PetscViewerBinarySetMPIIO() to enable it.
- Reworked the MATLAB objects sreader and freader to be called
  PetscOpenSocket and PetscOpenFile, now PetscBinaryWrite and
  PetscBinaryRead can be used on the same socket connection to send
  matrix/vectors in both directions. See
  src/ksp/ksp/examples/tutorials/ex41.c and ex41.m

```{rubric} SYS:
```

- PetscLogFlopsNoCheck() no longer exists; you can simply call
  PetscLogFlops() it no longer has a return in it.

```{rubric} ExternalPackages:
```