petsc-3.7.7 2017-09-25
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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 <shift> -

See Also

KSPComputeEigenvalues()

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