If文を用いない赤玉白玉モデルの実装例

ball_model_ex.py

# x=1: 袋a,  x=0: 袋b
# y=1: 赤玉, y=0:　白玉
def ball_model_no_if():
    x = pyro.sample("x", dist.Bernoulli(0.5))
    # xの値に応じてyの割合を変更
    y = pyro.sample("y", dist.Bernoulli(2.0/3.0))  * x + pyro.sample("y", dist.Bernoulli(1.0/4.0)) * (1 - x)
    return y

# plateを用いてi.i.dサンプリング
with pyro.plate("plate", size=10000):
    samples = ball_model_no_if()
print("var_type is {}, shape = {}".format(type(samples), samples.shape))
plt.hist(samples, bins=20)