PCPFMG#

the hypre PFMG multigrid solver

Options Database Keys#

-pc_pfmg_its - number of iterations of PFMG to use as preconditioner
-pc_pfmg_num_pre_relax - number of smoothing steps before coarse grid solve
-pc_pfmg_num_post_relax - number of smoothing steps after coarse grid solve
-pc_pfmg_tol - tolerance of PFMG
-pc_pfmg_relax_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 of coarse matrix generation, one of Galerkin,non-Galerkin
-pc_pfmg_skip_relax - 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