KSPGMRESSetHapTol#
Sets the tolerance for detecting a happy ending in GMRES (KSPGMRES
, KSPFGMRES
and KSPLGMRES
and others)
Synopsis#
#include "petscksp.h"
PetscErrorCode KSPGMRESSetHapTol(KSP ksp, PetscReal tol)
Logically Collective
Input Parameters#
ksp - the Krylov space solver context
tol - the tolerance for detecting a happy ending
Options Database Key#
-ksp_gmres_haptol
- set tolerance for determining happy breakdown
Note#
Happy ending is the rare case in KSPGMRES
where a very near zero matrix entry is generated in the upper Hessenberg matrix indicating
an ‘exact’ solution has been obtained. If you attempt more iterations after this point with GMRES unstable
things can happen.
The default tolerance value for detecting a happy ending with GMRES in PETSc is 1.0e-30.
See Also#
Level#
intermediate
Location#
Implementations#
KSPGMRESSetHapTol_GMRES() in src/ksp/ksp/impls/gmres/gmres.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages