#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 |