KSPQCGGetQuadratic#

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

Synopsis#

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

Collective

The quadratic function is

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

which satisfies the Euclidean Norm trust region constraint

\[ || D * s || \le delta, \]

where

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

advanced