class DoubleIndex implements Index {

  public Selection atMost(double value) {
    Selection selection = new BitmapBackedSelection();
    Double2ObjectSortedMap<IntArrayList> head =
        index.headMap(value + 0.000001); // we add 1 to get values equal
    // to the arg
    for (IntArrayList keys : head.values()) {
      addAllToSelection(keys, selection);
    }
    return selection;
  }

  public  DoubleIndex(DoubleColumn column);

}