petsc-3.13.6 2020-09-29
KSPSetCheckNormIteration
Sets the first iteration at which the norm of the residual will be computed and used in the convergence test.
Synopsis
#include "petscksp.h"
PetscErrorCode KSPSetCheckNormIteration(KSP ksp,PetscInt it)
Logically Collective on ksp
Input Parameter
| ksp | - Krylov solver context
|
| it | - use -1 to check at all iterations
|
Notes
Currently only works with KSPCG, KSPBCGS and KSPIBCGS
Use KSPSetNormType(ksp,KSP_NORM_NONE) to never check the norm
On steps where the norm is not computed, the previous norm is still in the variable, so if you run with, for example,
-ksp_monitor the residual norm will appear to be unchanged for several iterations (though it is not really unchanged).
See Also
KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetNormType()
Level
advanced
Location
src/ksp/ksp/interface/itcreate.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages