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# PCSYSPFMG

the hypre SysPFMG multigrid solver

## Options Database Keys

- -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 (Weighted- Jacobi|Red/Black-Gauss-Seidel) - relaxation type for the up and down cycles

## Notes

See `PCPFMG` for hypre’s PFMG that works for a scalar PDE and `PCSMG`

See `PCHYPRE` for hypre’s BoomerAMG algebraic multigrid solver

This is for CELL-centered descretizations

This must be used with the `MATHYPRESSTRUCT` matrix type.

This does not give access to all the functionality of hypres SysPFMG, it supports only one part, and one block per process defined by a PETSc `DMDA`.

## See Also

KSP: Linear System Solvers, `PCMG`, `MATHYPRESSTRUCT`, `PCPFMG`, `PCHYPRE`, `PCGAMG`, `PCSMG`

## Level

advanced

## Location

src/ksp/pc/impls/hypre/impl/ihypre.c

Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages