petsc-3.7.5 2017-01-01
MatSchurComplementSetAinvType
set the type of approximation used for the inverse of the (0,0) block used in forming Sp in MatSchurComplementGetPmat()
Synopsis
#include "petscksp.h"
PetscErrorCode MatSchurComplementSetAinvType(Mat S,MatSchurComplementAinvType ainvtype)
Not collective.
Input Parameters
| S | - matrix obtained with MatCreateSchurComplement() (or equivalent) and implementing the action of A11 - A10 ksp(A00,Ap00) A01
|
| ainvtype | - type of approximation used to form A00inv from A00 when assembling Sp = A11 - A10 A00inv A01:
MAT_SCHUR_COMPLEMENT_AINV_DIAG or MAT_SCHUR_COMPLEMENT_AINV_LUMP
|
Options database
-mat_schur_complement_ainv_type diag | lump
Note
Since the real Schur complement is usually dense, providing a good approximation to newpmat usually requires
application-specific information. The default for assembled matrices is to use the inverse of the diagonal of
the (0,0) block A00 in place of A00^{-1}. This rarely produces a scalable algorithm. Optionally, A00 can be lumped
before forming inv(diag(A00)).
See Also
MatSchurComplementAinvType, MatCreateSchurComplement(), MatGetSchurComplement(), MatSchurComplementGetPmat(), MatSchurComplementGetAinvType()
Level:advanced
Location:src/ksp/ksp/utils/schurm.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages