petsc-3.7.5 2017-01-01

KSPQCGGetQuadratic

Gets the value of the quadratic function, evaluated at the new iterate:

#include "petscksp.h" 
PetscErrorCode  KSPQCGGetQuadratic(KSP ksp,PetscReal *quadratic)

q(s) = g^T * s + 0.5 * s^T * H * s

which satisfies the Euclidian Norm trust region constraint

|| D * s || <= delta,

where

delta is the trust region radius, g is the gradient vector, and H is Hessian matrix, D is a scaling matrix.

Collective on KSP

ksp -the iterative context

quadratic -the quadratic function evaluated at the new iterate