KSPGMRESGetOrthogonalization#

Gets the orthogonalization routine used by KSPGMRES and KSPFGMRES.

Synopsis#

Not Collective

Input Parameter#

  • ksp - iterative context obtained from KSPCreate()

Output Parameter#

  • fcn - orthogonalization function

Calling Sequence of function#

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

Options Database Keys#

  • -ksp_gmres_classicalgramschmidt - Activates KSPGMRESClassicalGramSchmidtOrthogonalization() (default)

  • -ksp_gmres_modifiedgramschmidt - Activates KSPGMRESModifiedGramSchmidtOrthogonalization()

Notes#

Two orthogonalization routines are predefined, including KSPGMRESModifiedGramSchmidtOrthogonalization(), and the default KSPGMRESClassicalGramSchmidtOrthogonalization()

Use KSPGMRESSetCGSRefinementType() to determine if iterative refinement is used to increase stability.

See Also#

KSP: Linear System Solvers, KSPGMRESSetRestart(), KSPGMRESSetPreAllocateVectors(), KSPGMRESSetCGSRefinementType(), KSPGMRESSetOrthogonalization(), KSPGMRESModifiedGramSchmidtOrthogonalization(), KSPGMRESClassicalGramSchmidtOrthogonalization(), KSPGMRESGetCGSRefinementType()

Level#

intermediate

Location#

src/ksp/ksp/impls/gmres/gmres2.c

Implementations#

KSPGMRESGetOrthogonalization_GMRES in src/ksp/ksp/impls/gmres/gmres.c


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