[petsc-users] MatMPIAIJGetSeqAIJ implemented for fortran?

[Matthew Knepley]

On Mon, Jul 9, 2018 at 10:02 PM Marius Buerkle <mbuerkle at web.de> 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 <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/>
>


-- 
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/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20180709/e36977c7/attachment.html>