KSPComputeExtremeSingularValues

Computes the extreme singular values for the preconditioned operator. Called after or during KSPSolve() (SLESSolve()).

Synopsis

#include "petscksp.h" 
int KSPComputeExtremeSingularValues(KSP ksp,PetscReal *emax,PetscReal *emin)

Not Collective

Input Parameter

ksp -iterative context obtained from KSPCreate()

Output Parameters

emin, emax -extreme singular values

Notes

One must call KSPSetComputeSingularValues() before calling KSPSetUp() (or use the option -ksp_compute_eigenvalues) in order for this routine to work correctly.

Many users may just want to use the monitoring routine KSPSingularValueMonitor() (which can be set with option -ksp_singmonitor) to print the extreme singular values at each iteration of the linear solve.

Keywords