|-pc_syspfmg_its <its> number of iterations of SysPFMG to use as preconditioner|
|-pc_syspfmg_num_pre_relax <steps> number of smoothing steps before coarse grid|
|-pc_syspfmg_num_post_relax <steps> number of smoothing steps after coarse grid|
|-pc_syspfmg_tol <tol> tolerance of SysPFMG|
|-pc_syspfmg_relax_type||- relaxation type for the up and down cycles, one of Weighted-Jacobi,Red/Black-Gauss-Seidel|
This must be used with the MATHYPRESSTRUCT matrix type. This is less general than in hypre, it supports only one part, and one block per process defined by a PETSc DMDA. Also, only cell-centered variables.