needsToBeSched=new LinkedList();
    public RawFlattener(SIROperator toplevel)     {	this.SIRMap = new HashMap();	feedbackSplitters = new HashSet();	unique_id = 0;	//create the flat graph	createGraph(toplevel);	//now we need to fix up the graph a bit	//we need to add all the back edges of the splitter of a feedbacks	Iterator it = feedbackSplitters.iterator();	while(it.hasNext()) {	    ((FlatNode)it.next()).swapSplitterEdges();	    	}	    }