On 06/18/2013 02:48 PM, Cody Permann wrote: > > > > On Tue, Jun 18, 2013 at 12:41 PM, Jens Lohne Eftang > <[email protected] <mailto:[email protected]>> wrote: > > Hi all, > > > I'm solving a large 3D linear elasticity (steady) problem. My mesh has > 8.8million nodes, so since this is a vector-valued problem there's > around 26 million unknowns. > > The code is basically systems_of_equations_ex6 (except for the mesh > generation part, and I also do not compute stresses). > > I have configured petsc with --download-ml, and I am running my > program with > > mpirun -np 20 ./elasticity-opt -ksp_type cg -pc_type gamg > -pc_gamg_agg_nsmooths 1 -ksp_monitor -ksp_converged_reason > -log_summary > > that is, CG as the iterative solver and AMG as preconditioner. > > The problem is the huge amount of memory that this solve requires > --- I > have 128Gb memory, and I run out! Due to the large problem size I > was of > course expecting significant memory consumption, but not this bad. > I did > try ParallelMesh, but that did not change things. > > > > Is that total memory across all 20 processes, per node, or per > process? 128GB total is not unreasonable for a problem of this size. > Typically you would spread this out over several nodes though so it > could run. One way to drastically reduce total memory consumption > would be to implement threading for your Jacobian and residual callbacks.
Hmm ok... the memory consumption I reported was total across all 20 processes. I'll look into some solver options and see if I can get it under my 128 threshold. Thanks! > > Cody > > > Am I doing something obviously wrong here? > > > Thanks, > Jens > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Libmesh-users mailing list > [email protected] > <mailto:[email protected]> > https://lists.sourceforge.net/lists/listinfo/libmesh-users > > ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
