[petsc-users] Columnwise and 2D partitioning for matrices that have irregular sparsity patterns

[R. Oğuz Selvitopi]

That was fast.

Thanks.


On Fri, Jan 3, 2014 at 5:41 AM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> "R. Oğuz Selvitopi" <roguzsel at gmail.com> writes:
>
> > Hello,
> >
> > Is it possible to partition a parallel matrix in PETSc as follows:
> >
> > A B C
> > D E F
> > G H I
> >
> > The blocks A-D-G belong to processor 0 (A is the diagonal block, D and
> > G are off-diagonal blocks)
> >
> > The blocks B-E-H belong to processor 1 (E is the diagonal block, B and
> > H are off-diagonal blocks)
> >
> > The blocks C-F-I belong to processor 2 (I is the diagonal block, C and
> > F are off-diagonal blocks)
>
> Assemble the transpose, then either use MatMultTranspose or
> MatCreateTranspose.
>
> > Or, is it possible to have nine processors and each has a block of the
> > matrix above? Block A belongs to processor 0, block B belongs to
> > processor 1, and so on...
>
> Not with sparse matrices (except using MatShell, in which case you are
> responsible for the implementation).  You can do it for dense matrices
> (see MatElemental).
>



-- 
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Oguz.
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