mymath.py 文件源码

def binary_permutations(n_bits):
    """
    Given some number of bits, return a shape (2**n_bits, n_bits) boolean array containing every permoutation
    of those bits as a row.
    :param n_bits: An integer number of bits
    :return: A shape (2**n_bits, n_bits) boolean array containing every permoutation
        of those bits as a row.
    """
    return np.right_shift(np.arange(2**n_bits)[:, None], np.arange(n_bits-1, -1, -1)[None, :]) & 1