rand.py 文件源码

def sample_from_histogram(p, n_samples=1):
    """
    returns the indice of bin according to the histogram p

    @param p: histogram
    @type p: numpy.array
    @param n_samples: number of samples to generate
    @type n_samples: integer
    """

    from numpy import add, less, argsort, take, arange
    from numpy.random import random

    indices = argsort(p)
    indices = take(indices, arange(len(p) - 1, -1, -1))

    c = add.accumulate(take(p, indices)) / add.reduce(p)

    return indices[add.reduce(less.outer(c, random(n_samples)), 0)]