lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t sys);
lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys,
lmm_constraint_t cnst);
lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t sys);
lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys,
lmm_constraint_t cnst);