def _spark_calc_values_chunk(points):
    """
    Compute some basic information about the chunk points values

    The returned information are :
    * count : the number of points in chunk
    * max : the maximum value in chunk
    * min : the minimum value in chunk
    * sum : the sum of the values in chunk
    * sqr_sum : the sum of the square values in chunk (used for variance calculation)


    :param points: list of data values for each point in the chunk
    :type points: numpy.array

    :return: a dict composed of the basic information computed
    :rtype: dict
    """

    try:
        nb_points = len(points)
    except TypeError:
        return None

    if nb_points > 0:
        sum_chunk_value = sum(points)
        square_sum_chunk_value = sum([x * x for x in points])
        max_chunk_value = max(points)
        min_chunk_value = min(points)
    else:
        # Empty chunk, skip it
        return None

    return {
        "count": nb_points,
        "max": max_chunk_value,
        "min": min_chunk_value,
        "sum": sum_chunk_value,
        "sqr_sum": square_sum_chunk_value,
    }