[petsc-users] Does PETSc have some functions like A.*B, A./B in Matlab?

[Yujie]

Hi, Jeb

It looks MatGetRow() only can get the nonzero row values for sparse matrix.
It is not suitable for A./B if there are different formats between A and B.
Thanks.

Regards,
Yujie

On Wed, Oct 28, 2009 at 10:39 AM, Jed Brown <jed at 59a2.org> wrote:

> abhyshr at mcs.anl.gov wrote:
> > If A and B are vectors, then you can use VecPointwiseMult for A.*B and
> VecPointwiseDivide for A./B.
> > For matrices,pointwise multiplication and division functions are not
> provided in Petsc. One possible way to do
> > A.*B and A./B for matrices is to loop through the columns of the
> matrices,call MatGetColumnVector for each column of matrix A,B
> > and then call VecPointwiseMult/VecPointwiseDivide.
>
> This would be very inefficient because it produces dense output and
> PETSc matrices are row-aligned.  I would suggest using MatGetRow which
> is much faster and preserves sparsity.
>
> Jed
>
> >
> > Shri
> >
> > ----- Original Message -----
> > From: "Yujie" <recrusader at gmail.com>
> > To: "PETSc users list" <petsc-users at mcs.anl.gov>
> > Sent: Wednesday, October 28, 2009 10:21:34 AM GMT -06:00 US/Canada
> Central
> > Subject: Does PETSc have some functions like A.*B, A./B in Matlab?
> >
> > Dear PETSc Developers,
> >
> > Does PETSc provide some functions, like A.*B, A./B in Matlab? Thanks a
> lot.
> >
> > Regards,
> > Yujie
>
>
>
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