MatGalerkin#
Constructs the coarse grid problem matrix via Galerkin projection.
Synopsis#
#include "petscmat.h"
PetscErrorCode MatGalerkin(Mat restrct, Mat dA, Mat interpolate, MatReuse reuse, PetscReal fill, Mat *A)
If the interpolation and restriction operators are the same, uses MatPtAP().
If they are not the same, uses MatMatMatMult().
Once the coarse grid problem is constructed, correct for interpolation operators that are not of full rank, which can legitimately happen in the case of non-nested geometric multigrid.
Input Parameters#
restrct - restriction operator
dA - fine grid matrix
interpolate - interpolation operator
reuse - either
MAT_INITIAL_MATRIXorMAT_REUSE_MATRIXfill - expected fill, use
PETSC_DEFAULTif you do not have a good estimate
Output Parameter#
A - the Galerkin coarse matrix
Options Database Key#
-pc_mg_galerkin <both,pmat,mat,none> - for what matrices the Galerkin process should be used
See Also#
Matrices, Mat, MatPtAP(), MatMatMatMult()
Level#
developer
Location#
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages