1 /* 2 Context for conjugate gradient method (unconstrained minimization) 3 */ 4 5 6 #ifndef __TAO_CG_H 7 #define __TAO_CG_H 8 9 #include "tao-private/taosolver_impl.h" 10 11 typedef struct { 12 Vec G_old; 13 Vec X_old; 14 Vec W; /* work vector */ 15 16 PetscReal eta; /* Restart tolerance */ 17 PetscReal delta_max; /* Minimum value for scaling */ 18 PetscReal delta_min; /* Maximum value for scaling */ 19 20 21 /* The algorithm restarts when the gradient at the current point g_k, 22 and the gradient of the previous point, g_{k-1}, satisfy the 23 following inequality: 24 25 abs(inner(g_k, g_{k-1})) > eta * norm(g_k, 2)^2. */ 26 27 PetscInt ngradsteps; /* Number of gradient steps */ 28 PetscInt nresetsteps; /* Number of reset steps */ 29 30 PetscInt cg_type; /* Formula to use */ 31 } TAO_CG; 32 33 #endif /* ifndef __TAO_CG_H */ 34 35 36