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#
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