docs: @Override
    public void aggregate()
    {
      final IndexedInts keys = keySelector.getRow();
      for (int i = 0; i < valueSelectors.length; i++) {
        values[i] = valueSelectors[i].getDouble();
      }
      synchronized (this) {
        for (int i = 0, keysSize = keys.size(); i < keysSize; i++) {
          final String key = keySelector.lookupName(keys.get(i));
          sketch.update(key, values);
        }
      }
    }