void (*solve) (lmm_system_t));
/* Generic functions common to all models */
+void surf_action_init(void);
+void surf_action_exit(void);
e_surf_action_state_t surf_action_state_get(surf_action_t action); /* cannot declare inline since we use a pointer to it */
double surf_action_get_start_time(surf_action_t action); /* cannot declare inline since we use a pointer to it */
double surf_action_get_finish_time(surf_action_t action); /* cannot declare inline since we use a pointer to it */