# Changes: 2.0.28

## Changes

(See [Features] below)

```{rubric} General:
```

- No longer support PETSC_ARCH=sun4
- The macros in petscconf.h now begin with PETSC\_
- `PetscReal()` and `PetscImaginary()` are now
  `PetscRealPart()` `PetscImaginaryPart()`
- -optionstable -> -options_table -optionsleft -> -options_left but
  old left for compatibility

```{rubric} AO (Application Orderings):
```

```{rubric} TS (Timestepping Solvers):
```

- `TSSetMonitor()` now takes an additional final optional argument
  that monitor context.

```{rubric} SNES (Nonlinear Solvers):
```

- SNES_EQ_LS etc changed to drop \_, for example SNESEQLS
- Changed calling sequence of SNES monitoring routines to add an
  additional output parameter indicating why it converged or
  diverged.
- Added additional final argument to `SNESSetMonitor()` an
  optional destroy routine for the monitor context.
- Changed calling sequence of `MatSNESMFAddNullSpace()` to take
  `PCNullSpace` object rather than array of vectors.
- Added final ctx argument to `SNESGetFunction()`,
  `SNESGetGradient()` and `SNESGetMinimizationFunction()`

```{rubric} SLES (Linear Solvers):
```

- See PC and KSP
- `SLESSolveTrans()` is now `SLESSolveTranspose()`
- `SLESSolve()` now ALWAYS returns a 0 or positive iteration
  count. Call `KSPGetConvergedReason()` to see if converged or
  diverged and why.

```{rubric} KSP (Krylov Subspace Methods):
```

- Added additional final argument to `KSPSetMonitor()` an optional
  destroy routine for the monitor context.
- `KSPSolvetrans()` is now `KSPSolveTranspose()`
- Added flexible gmres (use fgmres or KSPFGMRES as the type) see
  `KSPFGMRESSetModifyPC()` for one way to change PC at each
  iteration.

```{rubric} PC (Preconditioners):
```

- `MGSetRestriction()` and `MGSetInterpolation()` now accept
  PETSc figures out which one it is based on the number of rows and
  columns. Now you don't need to use the Shell matrices if you
  computed it "the other way then PETSc use to expect".
- `PCApplyTrans()` is now `PCApplyTranspose()`
- options -pc_ilu_mat_ordering_type \<nd,...> and
  -pc_lu_mat_ordering_type \<nd,...> now set the ordering type.

```{rubric} MAT (Matrices):
```

- Added two additional arguments to
  `MatCreate(MPI_Comm comm,int             m,int n,int M,int N,Mat *)`
  where m and n are the local ownership sizes. To get the effect of
  the old `MatCreate()` use m and n equal to PETSC_DECIDE
- Changed `MatSetLocalToGlobalMappingBlocked()` to
  `MatSetLocalToGlobalMappingBlock()` so that it would be less
  then 32 characters long.
- `MatSolveTrans()`and `MatSolveTransAdd()` are now
  `MatSolveTransposeXXX()` `MatMultTrans()` and
  `MatMultTransAdd()`are now `MatMultTransposeXXX()`
- `MatCreateMPIAdj()` changed to `MatCreateMPICSR()`;
  `MatCreateSeqAdj()` dropped.
- Another `MatSetOption()`, `MAT_IGNORE_ZERO_ENTRIES` for AIJ
  matrices with `ADD_VALUES`.
- added matrix option `MAT_KEEP_ZEROED_ROWS` causes
  `MatZeroRows()` to keep the original nonzero data structure and
  just put 0.0 into the elements that are to be zeroed. Without this
  option it removes the locations from the nonzero structure.

```{rubric} DA (Distributed Arrays):
```

```{rubric} VEC (Vectors):
```

- Added VecGetArray2d() and VecRestoreArray2d()

```{rubric} IS (Index Sets):
```

- Added second argument to `ISInvertPermutation`() that
  indicates how many indices are to be stored on that processor;
  ignored for one processor code. If you use
  `ISInvertPermutation`() simply add a second argument of
  `PETSC_DECIDE`.

```{rubric} Draw (Graphics):
```

- DrawHistxxx changed to DrawHGxxx

```{rubric} Viewers:
```

```{rubric} System:
```

- Routines XXXRegister() are now XXXRegisterDynamic() used for
  registering new object types in dynamic libraries and
  XXXRegister_Private() is now XXXRegister() used to register new
  object types whose definitions are in the exectuable.
- The final argument to OptionsHasName() and OptionsGetXXX() is a
  PetscTruth * instead of an int\*
- PETSc functions and objects that began with Table now begin with
  PetscTable
- Changed these routines to return an error code. extern int
  PetscStrchr(const char[],char,char \*\*); extern int
  PetscStrrchr(const char[],char,char \*\*); extern int
  PetscStrstr(const char[],const char[],char \*\*); extern int
  PetscStrtok(const char[],const char[],char \*\*); extern int
  PetscStrlen(const char[],int \*); added PetscStrallocpy(const
  char[],char \*\*); PetscStrncmp() and PetscStrcasecmp() now return
  PETSC_TRUE as a final argument if the strings match else
  PETSC_FALSE. Note this means removing ! from your current tests
  and adding it where you don't have it.
- PetscMemcmp() now has a final argument of true for matching
  memories.
- The Fortran versions of the PetscStrxxx() and PetscMemxxx()
  routines also now have the error flag as the final argument
- PetscFree() now always returns an error code that may be checked
  with CHKERRQ(). On systems where free() returns a void (and the
  user has no access to an error condition in free(), PetscFree()
  returns 0 i.e. no error; on other systems it returns the error
  number from free.
- The BT bitarray macros are now prefixed with PetscBT

```{rubric} Error Handling:
```

```{rubric} Event Logging:
```

```{rubric} Fortran Interface:
```

## Features

(See [Changes] above)

```{rubric} General:
```

- When doing string substitutions in library directory paths etc one
  must use \$\{PETSC_DIR} \$\{BOPT} etc now instead of \$PETSC_DIR etc.
  Also you can put anything in \{anything} as long as it is an
  environmental variable or passed in the options database with
  -anything
- Added PetscEmacsclientErrorHandler() -on_error_emacs [machinename]
  to allow emacs to jump to error; can be used with any other error
  handler.
- So long as you have defined the macro \_\_FUNC\_\_ "main" before
  your main C/C++ subroutine you can use SETERRQ() and CHKERRQ()
  instead of SETERRA(), CHKERRA().

```{rubric} AO (Application Orderings):
```

```{rubric} TS (Timestepping Solvers):
```

```{rubric} SNES (Nonlinear Solvers):
```

- Added `SNESSetLineSearchParams()` and
  `SNESGetLineSearchParams()`, contributed by Matt Knepley.
- Added `SNESGetConvergedReason()` to find out if a
  `SNESSolve()` has converged/diverged and why
- Added `SNESMonitorVecUpdate()` and -snes_vecmonitor_update to
  display the Newton update at each iteration.

```{rubric} SLES (Linear Solvers):
```

- See PC and KSP

```{rubric} KSP (Krylov Subspace Methods):
```

- Added -ksp_gmres_krylov_monitor and `KSPGMRESKrylovMonitor()` to
  allow one to view the vectors in the Krylov space.

```{rubric} PC (Preconditioners):
```

- We now provide a drop tolerance based ILU for SeqAIJ matrix format
  via Yousef Saad's SPARSEKIT2 software. Use
  -pc_ilu_use_drop_tolerance \<dt,dtcol,rowmax> or
  `PCILUSetUseDropTolerance`(pc,dt,dtcol,rowmax).

```{rubric} MAT (Matrices):
```

```{rubric} DA (Distributed Arrays):
```

```{rubric} VEC (Vectors):
```

```{rubric} IS (Index Sets):
```

```{rubric} Draw (Graphics):
```

- `DrawCreate()` and `DrawOpenX()` now can take

```{rubric} Viewers:
```

- Added `ViewerASCIIUseTabs()` to allow turning off tabbing during
  certain viewer operations.
- Added `ViewerGetSingleton()`, ViewerRestoreSingleton() to allow
  managing the calling of a sequential viewer from within a parallel
  viewer.
- Added `ViewerASCIISynchronizedPrintf`(viewer,....)
- Binary and ASCII viewers can create compressed files by simply
  appending a .gz on the filename.
- PETSc now has a new viewer that generates rudimentary Postscript.
  Improvements, additions may be added as needed. `DrawOpenPS()`,
  or `DrawSetType(,DRAW_PS);` or -draw_type ps

```{rubric} System:
```

- using -trdump with PETSC_USE_STACK compile option (default for
  BOPT=g\*) will print the entire stack for each malloc, allow one to
  more easily track down where mallocs where made that where not
  freed.
- Added PetscSum_Op to replace MPI_SUM for reductions with
  MPIU_SCALAR
- Added PetscMaxSum_Op to do max on first half of entries and sum on
  second half.
- Added CHKMEMQ and CHKMEMA macros to help track down memory
  corruption.

```{rubric} Error Handling:
```

```{rubric} Event Logging:
```

```{rubric} Fortran Interface:
```

- Added Fortran 90 interface support for HP Convex and
  Solaris.machine.