Send all the output of view and -log_summary. Matt
On Fri, May 8, 2009 at 10:39 AM, Fredrik Bengzon < fredrik.bengzon at math.umu.se> wrote: > Hong, > Thank you for the suggestions, but I have looked at the EPS and KSP objects > and I can not find anything wrong. The problem is that it takes longer to > solve with 4 cpus than with 2 so the scalability seems to be absent when > using superlu_dist. I have stored my mass and stiffness matrix in the mpiaij > format and just passed them on to slepc. When using the petsc iterative > krylov solvers i see 100% workload on all processors but when i switch to > superlu_dist only two cpus seem to do the whole work of LU factoring. I > don't want to use the krylov solver though since it might cause slepc not to > converge. > Regards, > Fredrik > > Hong Zhang wrote: > >> >> Run your code with '-eps_view -ksp_view' for checking >> which methods are used >> and '-log_summary' to see which operations dominate >> the computation. >> >> You can turn on parallel symbolic factorization >> with '-mat_superlu_dist_parsymbfact'. >> >> Unless you use large num of processors, symbolic factorization >> takes ignorable execution time. The numeric >> factorization usually dominates. >> >> Hong >> >> On Fri, 8 May 2009, Fredrik Bengzon wrote: >> >> Hi Petsc team, >>> Sorry for posting questions not really concerning the petsc core, but >>> when I run superlu_dist from within slepc I notice that the load balance is >>> poor. It is just fine during assembly (I use Metis to partition my finite >>> element mesh) but when calling the slepc solver it dramatically changes. I >>> use superlu_dist as solver for the eigenvalue iteration. My question is: can >>> this have something to do with the fact that the option 'Parallel symbolic >>> factorization' is set to false? If so, can I change the options to >>> superlu_dist using MatSetOption for instance? Also, does this mean that >>> superlu_dist is not using parmetis to reorder the matrix? >>> Best Regards, >>> Fredrik Bengzon >>> >>> >>> >> > -- 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/20090508/3e0d3755/attachment.htm>
