#define make_elem_active(elem) xbt_swag_insert_at_head(elem,&(elem->constraint->active_element_set))
#define make_elem_inactive(elem) xbt_swag_remove(elem,&(elem->constraint->active_element_set))
#define make_elem_active(elem) xbt_swag_insert_at_head(elem,&(elem->constraint->active_element_set))
#define make_elem_inactive(elem) xbt_swag_remove(elem,&(elem->constraint->active_element_set))
s_xbt_swag_t element_set; /* a list of lmm_element_t */
s_xbt_swag_t active_element_set; /* a list of lmm_element_t */
s_xbt_swag_t element_set; /* a list of lmm_element_t */
s_xbt_swag_t active_element_set; /* a list of lmm_element_t */