On Aug 13, 2013, at 9:57 PM, Michele Rosso <mro...@uci.edu> wrote: > Hi Jed, > > I attached the output for both the runs you suggested. At the beginning of > each file I included the options I used. > > On a side note, I tried to run with a grid of 256^3 (exactly as before) but > with less levels, i.e. 3 instead of 4 or 5. > My system stops the run because of an Out Of Memory condition. It is really > odd since I have not changed anything except > - pc_mg_levels. I cannot send you any output since there is none. Do you > have any guess where the problem comes from?
By default it uses a direct solver (maybe even sequential) for the coarsest level; since the coarse level is big the direct solver requires too much memory. You could install PETSc with the ./configure option --download-superlu_dist and run with -mg_coarse_pc_type lu -mg_coarse_pc_factor_mat_solver_package superlu_dist Barry > Thanks, > > Michele > > On 08/13/2013 07:23 PM, Jed Brown wrote: >> Michele Rosso <mro...@uci.edu> >> writes: >> >>> The matrix arises from discretization of the Poisson equation in >>> incompressible flow calculations. >>> >> Can you try the two runs below and send -log_summary? >> >> -log_summary -ksp_monitor -ksp_view -ksp_converged_reason -pc_type mg >> -pc_mg_galerkin -pc_mg_levels 5 -mg_levels_ksp_type richardson >> -mg_levels_ksp_max_it 1 >> >> >> -log_summary -ksp_monitor -ksp_view -ksp_converged_reason -pc_type mg >> -pc_mg_galerkin -pc_mg_levels 5 -mg_levels_ksp_type richardson >> -mg_levels_ksp_max_it 1 -pc_mg_type full >> > > <output_mg_1.txt><output_mg_2.txt>
