petsc-3.8.4 2018-03-24

PCMGSetRestriction

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

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

Logically Collective on PC and Mat

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

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.

MG, set, multigrid, restriction, level