KSPGMRESSetCGSRefinementType

Sets the type of iterative refinement to use in the classical Gram-Schmidt orthogonalization used by KSPGMRES and other PETSc GMRES implementations.

Synopsis

#include "petscksp.h"  
PetscErrorCode KSPGMRESSetCGSRefinementType(KSP ksp, KSPGMRESCGSRefinementType type)

Logically Collective

Input Parameters

• ksp - the Krylov space solver context

• type - the type of refinement

  KSP_GMRES_CGS_REFINE_NEVER
  KSP_GMRES_CGS_REFINE_IFNEEDED
  KSP_GMRES_CGS_REFINE_ALWAYS

Options Database Key

• -ksp_gmres_cgs_refinement_type (refine_never|refine_ifneeded|refine_always) - refinement type

Notes

The default is KSP_GMRES_CGS_REFINE_NEVER

For a very small set of problems not using refinement, that is KSP_GMRES_CGS_REFINE_NEVER may be unstable, thus causing KSPSolve() to not converge.

See Also

KSP: Linear System Solvers, KSPGMRES, KSPGMRESSetOrthogonalization(), KSPGMRESCGSRefinementType, KSPGMRESClassicalGramSchmidtOrthogonalization(), KSPGMRESGetCGSRefinementType(), KSPGMRESGetOrthogonalization()

Level

intermediate

Location

src/ksp/ksp/impls/gmres/gmres.c

Implementations

KSPGMRESSetCGSRefinementType_GMRES() in src/ksp/ksp/impls/gmres/gmres.c

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