+ xbt_swag_remove(var,&(sys->variable_set));
+ if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
+ else xbt_swag_insert_at_tail(var,&(sys->variable_set));
+
+ for (i = 0; i < var->cnsts_number; i++) {
+ elem = &var->cnsts[i];
+ xbt_swag_remove(elem, &(elem->constraint->element_set));
+ if(weight) xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
+ else xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
+ }