# 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
 `PCMG`, `MATHYPRESSTRUCT`, `PCPFMG`, `PCHYPRE`, `PCGAMG`, `PCSMG`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/hypre/hypre.c.html#PCSYSPFMG">src/ksp/pc/impls/hypre/hypre.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/pc/impls/hypre/hypre.c)


[Index of all PC routines](index.md)  
[Table of Contents for all manual pages](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
