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 */