petsc-3.6.1 2015-08-06
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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).

Keywords

KSP, create, context, norms

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