docs: protected DBIDs findNeighbors(DBIDRef q, long[] nD, ArrayModifiableDBIDs S, Relation<V> relation) {
      // Weights for distance (= rectangle query)
      DistanceQuery<V> dq = relation.getDistanceQuery(new SubspaceMaximumDistanceFunction(nD));
  
      // TODO: add filtering capabilities into query API!
      // Until then, using the range query API will be unnecessarily slow.
      // RangeQuery<V> rq = relation.getRangeQuery(df, DatabaseQuery.HINT_SINGLE);
      ArrayModifiableDBIDs nC = DBIDUtil.newArray();
      for(DBIDIter it = S.iter(); it.valid(); it.advance()) {
        if(dq.distance(q, it) <= w) {
          nC.add(it);
        }
      }
      return nC;
    }