The problem is small enough that you might be able to use MUMPS. Matt
On Fri, Jun 12, 2009 at 9:31 AM, Lisandro Dalcin <dalcinl at gmail.com> wrote: > On Fri, Jun 12, 2009 at 11:13 AM, Christian > Klettner<christian.klettner at ucl.ac.uk> wrote: > > Sorry that I sent this twice. No subject in the first one. > > > > Dear PETSc Team, > > I am writing a CFD finite element code in C. From the discretization of > > the governing equations I have to solve a Poisson type equation which is > > really killing my performance. Which solver/preconditioner from PETSc or > > any external packages would you recommend? The size of my problem is from > > ~30000-100000 DOF per core. What kind of performance would I be able to > > expect with this solver/preconditioner? > > I would suggest KSPCG. As preconditioner I would use ML or > HYPRE/BoomerAMG (both are external packages) > > > I am using a 2*quad core 2.3 GHz Opteron. I have decomposed the domain > > with Parmetis. The mesh is unstructured. > > Also, I am writing a code which studies free surface phenomena so the > mesh > > is continually changing. Does this matter when choosing a > > solver/preconditioner? My left hand side matrix (A in Ax=b) does not > > change in time. > > ML has a faster setup that BoomerAMG, but the convergence is a bit > slower. If your A matrix do not change, then likely BoomerAMG will be > better for you. In any case, you can try both: just build PETSc with > both packages, then you can change the preconditioner by just passing > a command line option. > > > > > Best regards and thank you in advance, > > Christian Klettner > > > > Disclaimer: the convergence of multigrid preconditioners depends a lot > on your actual problem. What I've suggested is just my limited > experience in a few problems I've run solving electric potentials. > > > -- > Lisandro Dalc?n > --------------- > Centro Internacional de M?todos Computacionales en Ingenier?a (CIMEC) > Instituto de Desarrollo Tecnol?gico para la Industria Qu?mica (INTEC) > Consejo Nacional de Investigaciones Cient?ficas y T?cnicas (CONICET) > PTLC - G?emes 3450, (3000) Santa Fe, Argentina > Tel/Fax: +54-(0)342-451.1594 > -- 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20090612/ffab467a/attachment.htm>
