filters = new HashSet();
realTiles = new HashSet();
    public static void generateCode(FlatNode topLevel)     {	//create a set containing all the coordinates of all	//the nodes in the FlatGraph plus all the tiles involved	//in switching	//generate the code for all tiles containing filters	filters = new HashSet();	topLevel.accept(new TileCode(), new HashSet(), true);	tiles = new HashSet();	tiles.addAll(Simulator.initSchedules.keySet());	tiles.addAll(Simulator.steadySchedules.keySet());		Iterator tileIterator = tiles.iterator();	while(tileIterator.hasNext()) {	    Coordinate tile = (Coordinate)tileIterator.next();	    //do not generate code for this tile	    //if it contains a filter	    //we have already generated the code in the visitor	    if (filters.contains(tile))		continue;	    noFilterCode(tile);	}    }