# Docs: Changes: 2.2.1

CHANGES in PETSc 2.2.1

General:

- Introduced 4 new PETSc data types: PetscInt, PetscErrorCode, PetscMPIInt and PetscBLASInt. For 99% of users these are just int or integer*4 and you do not need to change your code.
- For users with more than roughly 2 billion unknowns you can run configure with --with-64-bit-ints and then PetscInt will represent 64 bit integers, long long int in C and integer*8 in Fortran. But the the other 3 types remain 32 bit (i.e. int in C and integer*4 in Fortran). Now you can index into vectors and matrices with virtually unlimited sizes.

Vec:

- VecSetStashInitialSize() -> VecStashSetInitialSize()
- VecConvertMPIToAll() and VecConvertMPIToZero() have been replaced with VecScatterCreateToAll() and VecScatterCreateToZero()

IS:

- ISSum() now has a throughput argument instead of one in and one output.

Mat:

- MatSetStashInitialSize() -> MatStashSetInitialSize()
- added MatFactorInfoInitialize()
- added MatStashGetInfo()
- added MatGetVecs()
- added MatIsSymmetric(), MatIsTranspose() now take a tolerance flag for equality (use 0.0 for identical)
- added MatMPIAIJSetPreallocationCSR() and MatMPIBAIJSetPreallocationCSR()

PC:

- ICC now uses Manteuffel shift by default
- If matrix is symmetric, PC defaults to ICC when possible, if you told with MatSetOption(mat,MAT_SYMMETRIC)
- PCSetVector() is gone (no longer needed)
- PCNullSpaceAttach() is gone, use KSPSetNullSpace()
- MatGetSubmatrices() now preserves symmetric flag of original matrix
- hypre BoomerAMG (-pc_type hypre -pc_hypre_type boomeramg) now uses one 1 cycle of multigrid as preconditioner (Previously it used either a decrease in residual of 10^-7 or a maximum of 20 iterations

KSP:

- Note that a relative residual tolerance now means that ||r_k|| < tol*||b||
- Removed KSPSetRhs() and KSPSetSolution(), pass them through KSPSolve() instead
- Added KSPSetNullSpace(), KSPGetNullSpace()

DA:

- Added DAGetGhostedCoordinates() and DAGetCoordinateDA() (see src/dm/da/examples/tutorials/ex3.c)
- Added DACoor2d and DACoor3d (see src/dm/da/examples/tutorials/ex3.c)
- DAGetInterpolation() now provides the correct interpolation for nonuniform grids using the coordinate information provided with DASetCoordinates(). (see src/dm/da/examples/tutorials/ex3.c)

config/configure.py:

- --with-c/f-blas-lapack -> --download-c/f-blas-lapack=yes
- --with-c/f-blas-lapack-if-needed -> --download-c/f-blas-lapack=ifneeded
- added --download-mpich=yes,no,ifneeded
- added --download-mpich-device=
- added --download-mpich-machines=[machines]
- added configure including download support for hypre, parmetis
- added configure support (without download) to Mumps, UMF, Superlu,SuperLU_dist,DSCPACK
- Made configure much more robust

SNES:

- Added -snes_converged_reason
- Added SNESSetRhs(snes,rhs) to allow for solving F(x) = rhs

TS:

DMMG:

- Added DMMGSetNullSpace()

SYS:

Fortran:

ExternalPackages: