petsc-3.7.7 2017-09-25

PCMGGetRScale

Gets the pointwise scaling for the restriction operator from level l to l-1.

#include "petscksp.h" 
PetscErrorCode PCMGGetRScale(PC pc,PetscInt l,Vec *rscale)

Collective on PC

	pc	- the multigrid context
	rscale	- the scaling
	l	- the level (0 is coarsest) to supply [Do not supply 0]

When evaluating a function on a coarse level one does not want to do F(R * x) one does F(rscale * R * x) where rscale is 1 over the row sums of R.

MG, set, multigrid, restriction, level