> On Jul 10, 2018, at 11:50 PM, Marius Buerkle <[email protected]> wrote:
>
> Sorry, I have yet another question. While it works well for MPIAIJ, I end up
> in a deadlock if I use MatCreateSubmatrix on a MPIDENSE matrix. Should
> MatCreateSubmatrix work on dense matricies ?
yes
> On Mon, Jul 9, 2018 at 10:02 PM Marius Buerkle <[email protected]> wrote:
> MatGetSubmatrix is in the current PETSc released called MatCreateSubmatrix.
> Is this correct ?
>
>
> Yep. I am old and cannot follow API changes anymore.
>
> Matt
>
> On Mon, Jul 9, 2018 at 8:38 PM Marius Buerkle <[email protected]> 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 <[email protected]> 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/
>
>
> --
> 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/
