Run with the additional option -pc_mg_log and send us the log file. Barry
Maybe we should make this the default somehow. On Sep 23, 2013, at 10:55 AM, Michele Rosso <[email protected]> wrote: > Hi, > > I am successfully using PETSc to solve a 3D Poisson's equation with CG + MG . > Such equation arises from a projection algorithm for a multiphase > incompressible flow simulation. > I set up the solver as I was suggested to do in a previous thread (title: > "GAMG speed") and run a test case (liquid droplet with surface tension > falling under the effect of gravity in a quiescent fluid). > The solution of the Poisson Equation via multigrid is correct but it becomes > progressively slower and slower as the simulation progresses (I am performing > successive solves) due to an increase in the number of iterations. > Since the solution of the Poisson equation is mission-critical, I need to > speed it up as much as I can. > Could you please help me out with this? > > I run the test case with the following options: > > -pc_type mg -pc_mg_galerkin -pc_mg_levels 5 -mg_levels_ksp_type > richardson -mg_levels_ksp_max_it 1 > -mg_coarse_pc_type lu -mg_coarse_pc_factor_mat_solver_package superlu_dist > -log_summary -ksp_view -ksp_monitor_true_residual -options_left > > Please find the diagnostic for the final solve in the attached file > "final.txt'. > Thank you, > > Michele > <final.txt>
