[petsc-users] Correct use of PCFactorSetMatOrderingType

[Matthew Knepley]

On Tue, Nov 6, 2018 at 9:47 AM Edoardo alinovi via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Dear users,
>
> I have a question about the correct use of the option
> "PCFactorSetMatOrderingType" in PETSc.
>
> I am solving a problem with 2.5M of unknowns distributed along 16
> processors and  I am using the block jacobi preconditioner and MPIAIJ
> matrix format. I cannot figure out if the above option can be useful or not
> in decreasing the computational time. Any suggestion or tips?
>

It depends on where the matrix comes from. If the initial ordering is bad,
it can make a big difference. If not, then it won't.

  Thanks,

     Matt


> Thank you very much for the kind help
>
> ------
>
> Edoardo Alinovi, Ph.D.
>
> DICCA, Scuola Politecnica
> Universita' di Genova
> 1, via Montallegro
> 16145 Genova, Italy
>
> email: edoardo.alinovi at dicca.unige.it
> Tel: +39 010 353 2540
>
>
>

-- 
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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