petsc-3.14.6 2021-03-30

PCMGSetInterpolation

Sets the function to be used to calculate the interpolation from l-1 to the lth level

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

Logically Collective on PC

	pc	- the multigrid context
	mat	- the interpolation operator
	l	- the level (0 is coarsest) to supply [do not supply 0]

Usually this is the same matrix used also to set the restriction 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.

advanced