pymc的安装还是pymc3？

（Installation — PyMC 5.17.0 documentation）安装最新版本的pymc（注意，现在pymc3已更名为pymc）。

Name: numpy
Version: 1.22.1

Name: pymc
Version: 5.6.1

Name: Theano
Version: 1.0.5

Name: Theano-PyMC
Version: 1.1.2

import numpy as np
import pymc as pm
import arviz as az
import matplotlib.pyplot as plt

if __name__ == '__main__':
    np.random.seed(42)
    true_mean = 5
    true_std = 2
    data = np.random.normal(true_mean, true_std, size=100)

    with pm.Model() as model:
        mean = pm.Normal('mean', mu=0, sigma=10)
        std = pm.HalfNormal('std', sigma=5)
        obs = pm.Normal('obs', mu=mean, sigma=std, observed=data)

    with model:
        trace = pm.sample(200, tune=100)

    az.plot_trace(trace)
    plt.show()