On Sun, Jul 26, 2015 at 8:48 AM, [email protected] < [email protected]> 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:[email protected]] > *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 <[email protected]> wrote: > > "[email protected]" <[email protected]> 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. > > >
