petsc-3.7.1 2016-05-15
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KSPGMRESGetOrthogonalization

Gets the orthogonalization routine used by GMRES and FGMRES.

Synopsis

#include "petscksp.h"  
PetscErrorCode  KSPGMRESGetOrthogonalization(KSP ksp,PetscErrorCode (**fcn)(KSP,PetscInt))
Not Collective Many br

Input Parameter

ksp -iterative context obtained from KSPCreate Many br

Output Parameter

fcn -orthogonalization function Many br

Calling Sequence of function

  errorcode = int fcn(KSP ksp,int it);
  it is one minus the number of GMRES iterations since last restart;
   i.e. the size of Krylov space minus one

Notes

Two orthogonalization routines are predefined, including Many br

KSPGMRESModifiedGramSchmidtOrthogonalization() Many br

KSPGMRESClassicalGramSchmidtOrthogonalization() - Default. Use KSPGMRESSetCGSRefinementType() to determine if Many briterative refinement is used to increase stability. Many br

Options Database Keys

-ksp_gmres_classicalgramschmidt - Activates KSPGMRESClassicalGramSchmidtOrthogonalization() (default) Many br
-ksp_gmres_modifiedgramschmidt - Activates KSPGMRESModifiedGramSchmidtOrthogonalization() Many br

Many br

Keywords

KSP, GMRES, set, orthogonalization, Gram-Schmidt, iterative refinement

See Also

KSPGMRESSetRestart(), KSPGMRESSetPreAllocateVectors(), KSPGMRESSetCGSRefinementType(), KSPGMRESSetOrthogonalization(),
KSPGMRESModifiedGramSchmidtOrthogonalization(), KSPGMRESClassicalGramSchmidtOrthogonalization(), KSPGMRESGetCGSRefinementType() Many br

Level:intermediate
Location:
src/ksp/ksp/impls/gmres/gmres2.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages