KSPLSQRSetExactMatNorm#
Compute exact matrix norm instead of iteratively refined estimate.
Synopsis#
#include "petscksp.h"
PetscErrorCode KSPLSQRSetExactMatNorm(KSP ksp, PetscBool flg)
Not Collective
Input Parameters#
ksp - iterative context
flg - compute exact matrix norm or not
Notes#
By default, flg = PETSC_FALSE. This is usually preferred to avoid possibly expensive computation of the norm.
For flg = PETSC_TRUE, we call MatNorm(Amat,NORM_FROBENIUS,&lsqr->anorm) which will work only for some types of explicitly assembled matrices.
This can affect convergence rate as KSPLSQRConvergedDefault() assumes different value of ||A|| used in normal equation stopping criterion.
See Also#
KSP: Linear System Solvers, KSPSolve(), KSPLSQR, KSPLSQRGetNorms(), KSPLSQRConvergedDefault()
Level#
intermediate
Location#
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages