[petsc-users] SuperLU MPI-problem

[Mark Adams]

On Sun, Jul 26, 2015 at 8:48 AM, Mahir.Ulker-Kaustell at tyrens.se <
Mahir.Ulker-Kaustell at tyrens.se> wrote:

>  Thank you very much for the input. I will test this approach. I have
> some reading (about the numerical techniques that you have implemented) to
> do as well, so it might take some time for me, but I’ll be back…
>
>
>
> What does NV abbreviate?
>

Naviers ... typing too fast


>
>
> Mahir
>
>
>
>
>
> *From:* Mark Adams [mailto:mfadams at lbl.gov]
> *Sent:* den 26 juli 2015 15:41
> *To:* Jed Brown
> *Cc:* Ülker-Kaustell, Mahir; Matthew Knepley; petsc-users
> *Subject:* Re: [petsc-users] SuperLU MPI-problem
>
>
>
> Coming in late to this thread but you are doing frequency domain NV.
>
>
>
> Start by getting your time domain (definite, no omega shift) solves
> working.  This can be a challenge for NV.  There are techiques for this but
> we do not have them.  Start with plane aggregation (-pc_gamg_nsmooths 0),
> this should be able to work OK, then try smoothing, this will probably not
> work.
>
>
>
> Now add the shift.  If you are shifting to high frequency then there is no
> hope w/o very special methods so use a direct solver.
>
>
>
> Mark
>
>
>
>
>
> On Wed, Jul 22, 2015 at 5:29 PM, Jed Brown <jed at jedbrown.org> wrote:
>
> "Mahir.Ulker-Kaustell at tyrens.se" <Mahir.Ulker-Kaustell at tyrens.se> writes:
> > I am solving Ax = b with a sparse, indefinite, symmetric, complex
> > matrix, can anything be said about the chances of success in using an
> > iterative method?
>
> Not without more information/experimentation.  You should check the
> literature for your problem domain to see what people claim is
> successful or does not work.
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20150727/083716d0/attachment.html>