[petsc-users] Serial solution of system in MPI FEM application

[Ivano Barletta]

Thanks

I've tried the first option, I get this compilation error

undefined reference to `matcreatesubmatrices_'

My PETSc version is 3.7.5, is this a feature of newer versions?

Ivano

Il giorno ven 16 apr 2021 alle ore 16:06 Matthew Knepley <knepley at gmail.com>
ha scritto:

> On Fri, Apr 16, 2021 at 9:46 AM Ivano Barletta <ivano.barletta at cmcc.it>
> wrote:
>
>> Dear all,
>>
>> I have an MPI FEM application with an elliptic problem that I
>> solve with PETSc. For debugging purposes I want to
>> let the master process to solve the global system.
>>
>> Is there any simple way in PETSc to gather the distributed matrix
>> (the type is MATMPIAIJ) on a single MPI process?
>>
>
> You could use
>
>
> https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatCreateSubMatrices.html
>
> to extract a single, serial matrix on process 0. However, you can do this
> with the solver automatically using
>
>
> https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCTELESCOPE.html
>
> If you have the memory, you can do this more simply with
>
>
> https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCREDUNDANT.html
>
>   Thanks,
>
>      Matt
>
>
>> Thanks,
>> Ivano
>>
>>
>>
>
> --
> 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.cse.buffalo.edu/~knepley/>
>
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