[petsc-users] MatMPIAIJGetSeqAIJ implemented for fortran?

[Matthew Knepley]

On Mon, Jul 9, 2018 at 8:38 PM Marius Buerkle <mbuerkle at web.de> wrote:

>  I see. What I want to do is to calculate the matrix product C=A*B'
> between two sparse matrices A=(A11 0 , A21 0) and B=(B11 0 , B21 0)  where
> C will be dense in the end but I just want to calculate some selected
> entries C_ij  of C. At the moment I extract submatricies for the
> corresponding rows and columns,
>

I think that is the right way, but you should only need MatGetSubmatrix for
that.

  Thanks,

     Matt


> so I was wondering if there is a simpler or performancer-wise faster way.
> I assume there is not such thing as a restricted MatMatMul which just
> calculated the lets say predefined nonzero entries of C.
>
>
> These are "internal" routines that we rarely expect end users to use since
> they are specific for particular matrix implementations. As such they are
> also kind of strange to use from Fortran since none of the AIJ data
> structures can be made visible to Fortran.
>
> Could you explain why you want them from Fortran and maybe we'll have
> alternative suggestions on how you can achieve the same effect.
>
> Barry
>
>
> > On Jul 5, 2018, at 3:05 AM, Marius Buerkle <mbuerkle at web.de> wrote:
> >
> > or MatMPIAIJGetLocalMatCondensed for that matter.
> >
> >
> >
> > Hi !
> >
> > Is MatMPIAIJGetSeqAIJ implemented for fortran?
> >
> > best,
> > Marius
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
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