for (int i = 0; i < number_of_constraints; i++) {
var->cnsts[i].enabled_element_set_hookup.next = nullptr;
var->cnsts[i].enabled_element_set_hookup.prev = nullptr;
for (int i = 0; i < number_of_constraints; i++) {
var->cnsts[i].enabled_element_set_hookup.next = nullptr;
var->cnsts[i].enabled_element_set_hookup.prev = nullptr;