nodeIds = new HashMap<SIROperator,Integer>();
opToId = new HashMap<SIROperator,Integer>(); flatToId = new HashMap<FlatNode,Integer>();
    public static void reset() {        counter = 0;        nodeIds = new HashMap<SIROperator,Integer>();        idToFlatNode = new HashMap<Integer,FlatNode>();        idToOperator = new HashMap<Integer,SIROperator>();    }