KSPPIPEFGMRESSetShift#

Set the shift parameter for the flexible, pipelined GMRES solver.

Synopsis#

#include "petscksp.h"  
PetscErrorCode KSPPIPEFGMRESSetShift(KSP ksp, PetscScalar shift)

A heuristic is to set this to be comparable to the largest eigenvalue of the preconditioned operator. This can be acheived with PETSc itself by using a few iterations of a Krylov method. See KSPComputeEigenvalues (and note the caveats there).

Logically Collective on ksp

Input Parameters#

  • ksp - the Krylov space context

  • shift - the shift

Options Database#

  • -ksp_pipefgmres_shift - set the shift parameter

See Also#

KSPComputeEigenvalues()

Level#

intermediate

Location#

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


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Index of all KSP routines
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