On Tue, Feb 16, 2016 at 10:12 AM, Harshad Sahasrabudhe <hsaha...@purdue.edu> wrote:
> Hi John, > > Thanks for the response. > > >> I'm using KrylovSchur eigensolver >>> in SLEPc and I find that the eigenvalue computation anti-scales when I >>> use >>> >> >> anti-scales? >> > > Yes, I get the following scaling > > Processes Eigensolver time(s) > 1 68.3037 > 2 51.9604 > 4 49.5286 > 8 66.7834 > 16 106.671 > 32 128.522 > > One node contains 16 processors, so the last time is for 2 nodes. > Even your scaling from 1->2 processors is very bad, let alone out to 32. Have you done any profiling? Even configuring libmesh with --enable-perflog would be better than nothing, and might help you figure out which parts of the code are not scaling. If it's not the Eigensolve, then you are focusing in the wrong place anyway. > Gauss quadrature. Having a diagonal pattern in B might fix the scaling and >>> increase the performance. >>> >>> Do you have any other suggestions on improving the scaling? >>> >> >> Use preconditioners which scale well, like AMG, if they make sense for >> your problem. >> > > I can try using different preconditioners. How do I set the preconditioner > for the eigensolver? > As David mentioned, you can use all the usual PETSc command line options (-pc_type, -ksp_type, etc.) but prefix them with "-st_" and they will get used by SLEPc. -- John ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
