# PCMGSetLevels

Sets the number of levels to use with MG. Must be called before any other MG routine.

### Synopsis

    #include "petscmg.h"
    PetscErrorCode PETSCKSP_DLLEXPORT PCMGSetLevels(PC pc,PetscInt levels,MPI_Comm *comms)

Collective on PC

### Input Parameters

| pc | - the preconditioner context
| levels | - the number of levels
| comms | - optional communicators for each level; this is to allow solving the coarser problems on smaller sets of processors. Use PETSC_NULL_OBJECT for default in Fortran

### Notes

If the number of levels is one then the multigrid uses the -mg_levels prefix for setting the level options rather than the -mg_coarse prefix.

### Keywords

MG, set, levels, multigrid

### See Also

PCMGSetType(), PCMGGetLevels()

Level:intermediate
Location:src/ksp/pc/impls/mg/mg.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages