docs: private void linearScanBatchKNN(ArrayDBIDs ids, List<KNNHeap> heaps) {
      final DistanceQuery<O> dq = distanceQuery;
      // The distance is computed on database IDs
      for(DBIDIter iter = getRelation().getDBIDs().iter(); iter.valid(); iter.advance()) {
        int index = 0;
        for(DBIDIter iter2 = ids.iter(); iter2.valid(); iter2.advance(), index++) {
          KNNHeap heap = heaps.get(index);
          heap.insert(dq.distance(iter2, iter), iter);
        }
      }
    }