public void addRanges(int partId, PERangeList list) {
		if (partId < 0 || partId >= rangesParts.length) {
			throw new IndexOutOfBoundsException("Partition " + 
					partId + " does not exist");
		}
		if(rangesParts[partId] == null) {
			rangesParts[partId] = new PERangeList();
		}
		rangesParts[partId].addAll(list);
	}