void *lmm_constraint_id(lmm_constraint_t cnst);
void *lmm_variable_id(lmm_variable_t var);
void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
void *lmm_constraint_id(lmm_constraint_t cnst);
void *lmm_variable_id(lmm_variable_t var);
void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,