KSPOrthogonalizationSetCGSRefinementType#
Sets the type of iterative refinement to use in the classical Gram-Schmidt orthogonalization used by KSPGMRES and other solvers.
Synopsis#
#include "petscksp.h"
PetscErrorCode KSPOrthogonalizationSetCGSRefinementType(KSP ksp, KSPOrthogonalizationCGSRefinementType type)
Logically Collective
Input Parameters#
ksp - the Krylov space solver context
type - the type of refinement
Options Database Key#
-ksp_orthogonalization_cgs_refinement_type (refine_never|refine_ifneeded|refine_always) - refinement type
Notes#
This option applies only if the orthogonalization method is classical Gram-Schmidt (CGS), see KSPOrthogonalizationSet().
The default refinement type is KSP_ORTHOGONALIZATION_CGS_REFINE_NEVER.
For a very small set of problems, not using refinement, that is KSP_ORTHOGONALIZATION_CGS_REFINE_NEVER, may be unstable, thus causing KSPSolve()
to not converge.
See Also#
KSP: Linear System Solvers, KSPOrthogonalizationSet(), KSPOrthogonalizationCGSRefinementType, KSPOrthogonalizationClassicalGramSchmidt(), KSPOrthogonalizationGetCGSRefinementType(),
KSPOrthogonalizationGet()
Level#
intermediate
Location#
src/ksp/ksp/interface/orthog.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages