On Wed, Dec 19, 2012 at 10:00 AM, Daniel Arndt <daniel.arndt at stud.uni-goettingen.de> wrote: >>> Thank you Barry for your suggestions. >>> The error I get is now KSP_DIVERGED_INDEFINITE_PC. The matrix that I try >>> to invert is actually symmetric and positive definite. I was not aware that >>> this can lead to a indefinite preconditioner. > >> Absolutely. Many preconditioners do not retain this feature even in >> exact precision and with numerical effects it can even appear unexpected. >> By default BoomAMG doesn't retain this. > > Is there then a possibility to tell the BlockJacobi preconditioner to be > positive definit as there is for the BoomerAMG preconditioner via > -pc_hypre_boomeramg_relax_type_all symmetric-SOR/Jacobi?
Block-Jacobi is just a container. You can choose the inner solver to respect this. Matt > Bests > Daniel > > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener
