def distribution_schedule(n, total):
    """
    Determines the type of probability to use in the `crossover` function, based
    on the number of generations which have occured.

    Args:
        n (int): Number of elapsed generations.
        total (int): Total number of expected generations.

    Returns:
        str: Describes a type of probability distribution.
    """
    if n < 4 * total/5:
        return 'linear'
    else:
        return 'softmax_linear'