PETSc 2.3.1 release

[Barry Smith]

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 Portable, Extensible Toolkit for Scientific Computation (PETSc)
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               http://www.mcs.anl.gov/petsc

 We are pleased to announce the release of the PETSc 2.3.1 parallel
 software libraries for the implicit solution of PDEs and related
 problems.

 There are no MAJOR interface changes, the minor changes are listed at

 http://www-unix.mcs.anl.gov/petsc/petsc-as/documentation/changes/231.html
 please check these changes before compiling your codes.

 You can download from
 http://www-unix.mcs.anl.gov/petsc/petsc-as/download/index.html and
 and the installataion instructions are at
 http://www-unix.mcs.anl.gov/petsc/petsc-as/documentation/installation.html

 As always, please send bug reports, questions, and requests for new
 features to petsc-maint at mcs.anl.gov.

 Thanks for your continued support.

 The PETSc developers,
 Satish, Matt, Victor, Barry and Hong