KSP_GMRES_CGS_REFINE_ALWAYS#

Do two steps of the classical (unmodified) Gram-Schmidt process.

Notes#

This is roughly twice the cost of KSP_GMRES_CGS_REFINE_NEVER because it performs the process twice but it saves the extra norm calculation needed by KSP_GMRES_CGS_REFINE_IFNEEDED.

You should only use this if you absolutely know that the iterative refinement is needed.

See Also#

KSP: Linear System Solvers, KSPGMRES, KSPGMRESCGSRefinementType, KSPGMRESClassicalGramSchmidtOrthogonalization(), KSPGMRESSetOrthogonalization(), KSP, KSPGMRESGetOrthogonalization(), KSPGMRESSetCGSRefinementType(), KSPGMRESGetCGSRefinementType(), KSP_GMRES_CGS_REFINE_IFNEEDED, KSP_GMRES_CGS_REFINE_ALWAYS, KSPGMRESModifiedGramSchmidtOrthogonalization()

Level#

advanced

Location#

include/petscksp.h


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