PCPFMG#

the hypre PFMG multigrid solver

Options Database Keys#

-pc_pfmg_its its - number of iterations of PFMG to use as preconditioner
-pc_pfmg_num_pre_relax steps - number of smoothing steps before coarse grid solve
-pc_pfmg_num_post_relax steps - number of smoothing steps after coarse grid solve
-pc_pfmg_tol tol - tolerance of PFMG
-pc_pfmg_relax_type type - relaxation type for the up and down cycles, one of Jacobi,Weighted-Jacobi,symmetric-Red/Black-Gauss-Seidel,Red/Black-Gauss-Seidel
-pc_pfmg_rap_type type - type of coarse matrix generation, one of Galerkin,non-Galerkin
-pc_pfmg_skip_relax (0|1) - skip relaxation on certain grids for isotropic problems. This can greatly improve efficiency by eliminating unnecessary relaxations when the underlying problem is isotropic, one of 0,1

This is for CELL-centered descretizations

See PCSYSPFMG for a version suitable for systems of PDEs, and PCSMG

See PCHYPRE for hypre’s BoomerAMG algebraic multigrid solver

This must be used with the MATHYPRESTRUCT matrix type.

This provides only some of the functionality of PFMG, it supports only one block per process defined by a PETSc DMDA.

advanced