PETSc version 3.15.5
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# PCMGSetRestriction

Sets the function to be used to restrict dual vectors from level l to l-1.

### Synopsis

    #include "petscksp.h"
    PetscErrorCode  PCMGSetRestriction(PC pc,PetscInt l,Mat mat)

Logically Collective on PC

### Input Parameters

| pc | - the multigrid context
| l | - the level (0 is coarsest) to supply [Do not supply 0]
| mat | - the restriction matrix

### Notes

Usually this is the same matrix used also to set the interpolation for the same level.

One can pass in the interpolation matrix or its transpose; PETSc figures out from the matrix size which one it is.

If you do not set this, the transpose of the Mat set with PCMGSetInterpolation() is used.

### See Also

PCMGSetInterpolation()

### Level

advanced

### Location

src/ksp/pc/impls/mg/mgfunc.c
Index of all PC routines
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Index of all manual pages