petsc-master 2019-08-22
Report Typos and Errors

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