#include "petscksp.h" PetscErrorCode KSPSetCheckNormIteration(KSP ksp,PetscInt it)Logically Collective on ksp
|ksp||- Krylov solver context|
|it||- use -1 to check at all iterations|
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).