code: private int getBucket(double value) {
  		assert (value >= m_min_value && value <= m_max_value);
  		int bucket = (int) ((value - m_min_value) / m_dy);
  		return bucket;
  	}
docs: Adds new element to the bucket builder. The value must be between
  min_value and max_value.
  
  @param The
  value used for bucketing.
  @param The
  index of the element to store in the buffer. Usually it is an
  index into some array, where the real elements are stored.