result.setParent(null);
    public SIRStream toplevel() {	// lift before and after	Lifter.lift(str);	// debug setup	long start = System.currentTimeMillis();	// calculate partitions	StreamTransform st = calcPartitions();	if (DEBUG) { st.printHierarchy(); }	// debug output	System.err.println("Linear partitioner took " + 			   (System.currentTimeMillis()-start)/1000 + " secs to calculate partitions.");	// perform partitioning transformations	SIRStream result = st.doTransform(str);	// remove unnecessary identities	Lifter.eliminateIdentities(result);	// lift before and after	Lifter.lift(result);	// reclaim children here, since they might've been shuffled	// around in the config process	if (result instanceof SIRContainer) {	    ((SIRContainer)result).reclaimChildren();	}	return result;    }