MatSetNearNullSpace#
attaches a null space to a matrix, which is often the null space (rigid body modes) of the operator without boundary conditions This null space will be used to provide near null space vectors to a multigrid preconditioner built from this matrix.
Synopsis#
#include "petscmat.h"
PetscErrorCode MatSetNearNullSpace(Mat mat, MatNullSpace nullsp)
Logically Collective
Input Parameters#
mat - the matrix
nullsp - the null space object
Notes#
Overwrites any previous near null space that may have been attached
You can remove the null space by calling this routine with an nullsp of NULL
See Also#
Matrices, Mat, MatNullSpace, MatCreate(), MatNullSpaceCreate(), MatSetNullSpace(), MatNullSpaceCreateRigidBody(), MatGetNearNullSpace()
Level#
advanced
Location#
Examples#
src/snes/tutorials/ex56.c
src/ksp/ksp/tutorials/ex49.c
src/ksp/ksp/tutorials/ex56.c
src/ksp/ksp/tutorials/ex72.c
src/ksp/ksp/tutorials/ex59.c
src/ksp/ksp/tutorials/ex71.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages