petsc-3.8.4 2018-03-24
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 on Mat and MatNullSpace
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
MatCreate(), MatNullSpaceCreate(), MatSetNullSpace(), MatNullSpaceCreateRigidBody(), MatGetNearNullSpace()
Level:advanced
Location:src/mat/interface/matrix.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages
Examples
src/ksp/ksp/examples/tutorials/ex10.c.html
src/ksp/ksp/examples/tutorials/ex49.c.html
src/ksp/ksp/examples/tutorials/ex56.c.html