PETSc version 3.17.5

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 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).

Level

advanced

Location