Can you run with the additional option -ksp_view_mat binary and email the resulting file which will be called binaryoutput to petsc-ma...@mcs.anl.gov
Barry > On Jul 13, 2016, at 2:30 PM, Safin, Artur <aks084...@utdallas.edu> wrote: > > Dear PETSc community, > > I am working on solving a Helmholtz problem with PML. The issue is that I am > finding it very hard to deal with the resulting matrix system; I can get the > correct solution for coarse meshes, but it takes roughly 2-4 times as long to > converge for each successively refined mesh. I've noticed that without PML, I > do not have problems with convergence speed. > > I am using the GMRES solver with GAMG as the preconditioner (with > block-Jacobi preconditioner for the multigrid solves). I have also tried to > assemble a separate preconditioning matrix with the complex shift 1+0.5i, > that does not seem to improve the results. Currently I am running with > > -ksp_type fgmres \ > -pc_type gamg \ > -mg_levels_pc_type bjacobi \ > -pc_mg_type full \ > -ksp_gmres_restart 150 \ > > Can anyone suggest some way of speeding up the convergence? Any help would be > appreciated. I am attaching the output from kspview. > > Best, > > Artur > > <kspview>
