petsc-3.8.4 2018-03-24

KSPComputeExplicitOperator

Computes the explicit preconditioned operator, including diagonal scaling and null space removal if applicable.

Synopsis

#include "petscksp.h" 
PetscErrorCode  KSPComputeExplicitOperator(KSP ksp,Mat *mat)

Collective on KSP

Input Parameter

ksp -the Krylov subspace context

Output Parameter

mat -the explict preconditioned operator

Notes

This computation is done by applying the operators to columns of the identity matrix.

Currently, this routine uses a dense matrix format when 1 processor is used and a sparse format otherwise. This routine is costly in general, and is recommended for use only with relatively small systems.

Keywords