[petsc-users] Using Petsc with multiple RHS

[Matthew Knepley]

On Mon, Dec 12, 2011 at 3:10 AM, Alexander Grayver
<agrayver at gfz-potsdam.de>wrote:

> Hi Barry,
>
> Thanks for answer. I should have asked about that from the very beginning
> actually.
> I get 2 times decrease in performance with 20 RHS, I can imagine how slow
> it will be when I will use thousands of them,
> moreover it will require a lot of memory to store them as a dense matrix.
>
> On 11.12.2011 18:50, Barry Smith wrote:
>
>> On Dec 11, 2011, at 9:29 AM, Alexander Grayver wrote:
>>    One by one
>>
>
> I'm wondering why? All main direct packages like MUMPS, SuperLU_DIST,
> PaSTiX support multiple RHS.
>

We don't need it for the vast majority of problems.


>     We do not handle a sparse right hand side.
>
>
Since I already transferred my code to PETSc anyway, my question now if
> it's possible to implement sparse multiple RHS and solve them
> simultaneously?
> Something like MatMatSolveSparse. I would implement it myself, the
> question is there a way to integrate it into PETSc as a patch or something
> like that?
>

You can just implement MatMatSolve for another matrix type, like AIJ
(although you probably want the transpose).

   Matt


> Regards,
> Alexander
>



-- 
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
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