1: /*
2: Context for conjugate gradient method (unconstrained minimization)
3: */
5: #ifndef __TAO_CG_H
8: #include <petsc/private/taoimpl.h>
10: typedef struct {
11: Vec G_old;
12: Vec X_old;
13: Vec W; /* work vector */
15: PetscReal eta; /* Restart tolerance */
16: PetscReal delta_max; /* Minimum value for scaling */
17: PetscReal delta_min; /* Maximum value for scaling */
19: /* The algorithm restarts when the gradient at the current point g_k,
20: and the gradient of the previous point, g_{k-1}, satisfy the
21: following inequality:
23: abs(inner(g_k, g_{k-1})) > eta * norm(g_k, 2)^2. */
25: PetscInt ngradsteps; /* Number of gradient steps */
26: PetscInt nresetsteps; /* Number of reset steps */
28: PetscInt cg_type; /* Formula to use */
29: } TAO_CG;
31: #endif /* ifndef __TAO_CG_H */