split_to_uniform_ranges.py

def split_to_uniform_ranges(n, n_parts):
    """
    Split n into n_parts where the max difference among parts is 1

    :param int n: the number to be split
    :param int n_parts: The number of parts with which n will be split
    :return: n_part tuples that indicate the stat-end of the ranges
    """
    n, n_parts = numpy.int32(n), numpy.int32(n_parts)

    # compute the average size of each part and the remainder to be distributed
    # among the parts
    n_mean = numpy.int32(numpy.float64(n) / numpy.float64(n_parts))
    n_remaining = n % (n_mean * n_parts)

    if n_remaining == 0:
        # number of parts is an integer multiple of the original range, all
        # the parts have the same range size
        xs = numpy.arange(n_parts) * n_mean
        xe = xs + n_mean
    else:
        # number of parts is not an integer multiple of the original range,
        # distribute the remainder on the first parts. The remainder is always
        # less than n_parts
        _xs = numpy.arange(n_remaining) * (n_mean + 1)
        _xe = _xs + (n_mean + 1)

        xs = numpy.hstack(
            (
                _xs,
                numpy.arange(n_parts - n_remaining) * n_mean + _xe[-1]
            )
        )
        xe = numpy.hstack(
            (
                _xe,
                numpy.arange(n_parts - n_remaining) * n_mean + _xe[-1] + n_mean
            )
        )

    assert (xe - xs).sum() - n == 0

    return zip(xs, xe)