What problems are you having again with GAMG? Are you problems unsymmetric?
ML has several coarsening strategies available and I think the default does aggregation locally and does not aggregate across processor subdomains. If you have poorly shaped domains then you want to use a global coarsening method (these are not expensive). Mark On Jul 9, 2012, at 12:17 PM, John Mousel wrote: > Mark, > > I still haven't had much luck getting GAMG to work consistently for my > Poisson problem. ML seems to work nicely on low core counts, but I have a > problem where I can get long thin portions of grid on some processors instead > of nice block like chunks at high core counts, which leads to a pretty tough > time for ML. > > John > > On Mon, Jul 9, 2012 at 10:58 AM, John Mousel <john.mousel at gmail.com> wrote: > Getting rid of the Hypre option seemed to be the trick. > > On Mon, Jul 9, 2012 at 10:40 AM, Mark F. Adams <mark.adams at columbia.edu> > wrote: > Google PTL_NO_SPACE and you will find some NERSC presentations on how to go > about fixing this. (I have run into these problems years ago but forget the > issues) > > Also, I would try running with a Jacobi solver to see if that fixes the > problem. If so then you might try > > -pc_type gamg > -pc_gamg_agg_nsmooths 1 > -pc_gamg_type agg > > This is a built in AMG solver so perhaps it plays nicer with resources ... > > Mark > > On Jul 9, 2012, at 10:57 AM, John Mousel wrote: > > > I'm running on Kraken and am currently working with 4320 cores. I get the > > following error in KSPSolve. > > > > [2711]: > > (/ptmp/ulib/mpt/nightly/5.3/120211/mpich2/src/mpid/cray/src/adi/ptldev.c:2046) > > PtlMEInsert failed with error : PTL_NO_SPACE > > MHV_exe: > > /ptmp/ulib/mpt/nightly/5.3/120211/mpich2/src/mpid/cray/src/adi/ptldev.c:2046: > > MPIDI_CRAY_ptldev_desc_pkt: Assertion `0' failed. > > forrtl: error (76): Abort trap signal > > Image PC Routine Line Source > > MHV_exe 00000000014758CB Unknown Unknown Unknown > > MHV_exe 000000000182ED43 Unknown Unknown Unknown > > MHV_exe 0000000001829460 Unknown Unknown Unknown > > MHV_exe 00000000017EDE3E Unknown Unknown Unknown > > MHV_exe 00000000017B3FE6 Unknown Unknown Unknown > > MHV_exe 00000000017B3738 Unknown Unknown Unknown > > MHV_exe 00000000017B2B12 Unknown Unknown Unknown > > MHV_exe 00000000017B428F Unknown Unknown Unknown > > MHV_exe 000000000177FCE1 Unknown Unknown Unknown > > MHV_exe 0000000001590A43 Unknown Unknown Unknown > > MHV_exe 00000000014F909B Unknown Unknown Unknown > > MHV_exe 00000000014FF53B Unknown Unknown Unknown > > MHV_exe 00000000014A4E25 Unknown Unknown Unknown > > MHV_exe 0000000001487D57 Unknown Unknown Unknown > > MHV_exe 000000000147F726 Unknown Unknown Unknown > > MHV_exe 000000000137A8D3 Unknown Unknown Unknown > > MHV_exe 0000000000E97BF2 Unknown Unknown Unknown > > MHV_exe 000000000098EAF1 Unknown Unknown Unknown > > MHV_exe 0000000000989C20 Unknown Unknown Unknown > > MHV_exe 000000000097A9C2 Unknown Unknown Unknown > > MHV_exe 000000000082FF2D axbsolve_ 539 > > PetscObjectsOperations.F90 > > > > This is somewhere in KSPSolve. Is there an MPICH environment variable that > > needs tweaking? I couldn't really find much on this particular error. > > The solver is BiCGStab with Hypre as a preconditioner. > > > > -ksp_type bcgsl -pc_type hypre -pc_hypre_type boomeramg -ksp_monitor > > > > Thanks, > > > > John > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120709/7f46e1cc/attachment.html>
