if (twoStage.getPeekInt()-twoStage.getPopInt()>0) {
if (twoStage.getInitPop()>0) {
    private static boolean isFissable(SIRFilter filter) {	if (filter instanceof SIRTwoStageFilter) {	    SIRTwoStageFilter twoStage = (SIRTwoStageFilter)filter;	    if (twoStage.getPeekInt()-twoStage.getPopInt()>0) {		return false;	    }	}	return true;    }