KSPSetCheckNormIteration#
Sets the first iteration at which the norm of the residual will be computed and used in the convergence test of KSPSolve() for the given KSP context
Synopsis#
#include "petscksp.h"
PetscErrorCode KSPSetCheckNormIteration(KSP ksp, PetscInt it)
Logically Collective
Input Parameters#
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).
Certain methods such as KSPGMRES always compute the residual norm, this routine will not change that computation, but it will
prevent the computed norm from being checked.
See Also#
KSP: Linear System Solvers, KSP, KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetNormType(), KSPSetLagNorm()
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