*/
private Long2LongRBTreeMap computeTermFrequencies(
ObjectArrayList<DocumentScoreInfo<Reference2ObjectMap<Index, SelectedInterval[]>>> results)
throws IOException {
Long2LongRBTreeMap relFreq = new Long2LongRBTreeMap();
relFreq.defaultReturnValue(0);
for (int i = 0; i < min(k, results.size()); i++) {
Document document = collection
.document(results.get(i).document);
Reader reader = (Reader) document.content(fieldIndex);