new PETSc 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 2.3.0

The CHANGES in this release are a bit more extensive then usual.

1) You MUST use config/configure.py to install PETSc, see
   http://www-unix.mcs.anl.gov/petsc/petsc-as/documentation/installation.html

2) The BOPT option to determine optimization/debugging and C/C++ compiles
   is GONE. Now you  use a different PETSC_ARCH (for example linux-g and
   linux-O) for different optimizations and set the optimization as a 
   config/configure.py option. See
   http://www-unix.mcs.anl.gov/petsc/petsc-as/documentation/changes/230.html

3)* The prototypes of many methods, for example VecScale, MatShift, ... have 
   been changed to take the Vec or Mat object as the FIRST argument, otherwise
   the arguments are the same as before. See 
   http://www-unix.mcs.anl.gov/petsc/petsc-as/documentation/changes/230.html
   for a complete list of the functions changed.

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,


* this change was made to make all the PETSc calls more "object oriented"
so we could have the same calling sequences for our new PYTHON PETSc binding.