void reconnect() {
        if (deconnected()) {
            if (ToulBar2::verbose >= 3) cout << "reconnect " << this << endl;
			assert(linkX->prev == NULL && linkX->next == NULL);
            x->getConstrs()->push_back(linkX, true);
			assert(linkY->prev == NULL && linkY->next == NULL);
            y->getConstrs()->push_back(linkY, true);
        }
    }