*/
protected DBIDs computeSubspace(Vector<IntIntPair> subspace, ArrayList<ArrayList<DBIDs>> ranges) {
HashSetModifiableDBIDs ids = DBIDUtil.newHashSet(ranges.get(subspace.get(0).first - 1).get(subspace.get(0).second));
// intersect all selected dimensions
for(int i = 1; i < subspace.size(); i++) {
DBIDs current = ranges.get(subspace.get(i).first - 1).get(subspace.get(i).second);
ids.retainAll(current);
if(ids.size() == 0) {
break;
}
}