PETSc solver options

Using PETSc with libMesh

• Use command line -ksp_type to choose the PETSc solver kind.
  • Options are: richardson, chebychev, cg, gmres, tcqmr, bcgs, cgs, tfqmr, cr, lsqr, bicg, or preonly.
• Use -ksp_gmres_restart with gmres and ksp_richardson_scale for richardson.
• Use command line -pc_type to choose the PETSc preconditioner.
  • Options are: jacobi, bjacobi, sor, eisenstat, icc, ilu, asm, ksp, lu, or cholesky
  • Loads of options exist for using these preconditioners as well. See most recent PETSc manual.
  • Loads of externally supplied solvers as well that need to be hooked in. An important one for our work is BoomerAMG from HYPRE. Use as follows: -pc_type hypre -pc_type_hypre boomeramg -ksp_type richardson to just use BoomerAMG to solve. See PETSc FAQ and manual for more options.
    • Options from HYPRE (and for -pc_type_hypre) pilut, parasails, boomeramg, euclid
    • Note that it is best to use BoomerAMG with gmres because the AMG preconditioner by default is not symmetric.
• Use command line -log_summary to get lots of PETSc information about your run (Others claim that -log_info works too but I didn't find this with a 2.3.2-p7 version of PETSc.)
• Use -ksp_rtol, -ksp_atol, -ksp_divtol, and -ksp_max_it for setting other options.
• Monitor convergence with -ksp_monitor and see info about preconditioners etc. with -ksp_view.