On Tue, Jun 18, 2013 at 12:41 PM, Jens Lohne Eftang <[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. 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] > 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
