pymc3 创建 pm 时无法解释的类型错误.正态变量

Question

以下代码取自许多简单 pymc3 用法的示例：

import os
os.environ['MKL_THREADING_LAYER'] = 'GNU'
import pymc3 as pm
with pm.Model() as model:
    alpha = pm.Normal('alpha', mu=0, sigma=1)

出于某种原因，它会引发以下异常：

Traceback (most recent call last):
   File "test2.py", line 5, in <module>
    alpha = pm.Normal('alpha', mu=0, sigma=1)
  File "C:Users%USERNAME%AppDataLocalContinuumanaconda3libsite- 
packagespymc3distributionsdistribution.py", line 41, in __new__
    dist = cls.dist(*args, **kwargs)
  File "C:Users%USERNAME%AppDataLocalContinuumanaconda3libsite- 
packagespymc3distributionsdistribution.py", line 52, in dist
    dist.__init__(*args, **kwargs)
  File "C:Users%USERNAME%AppDataLocalContinuumanaconda3libsite- 
packagespymc3distributionscontinuous.py", line 404, in __init__
    super(Normal, self).__init__(**kwargs)
  File "C:Users%USERNAME%AppDataLocalContinuumanaconda3libsite- 
packagespymc3distributionsdistribution.py", line 180, in __init__
    shape, dtype, defaults=defaults, *args, **kwargs)
 TypeError: __init__() got an unexpected keyword argument 'sigma'

此错误的原因是什么？

我已经尝试过 3.5 和 3.6 版本以及 pymc3。

Answer 1

你应该使用sd而不是sigma：

import os
os.environ['MKL_THREADING_LAYER'] = 'GNU'
import pymc3 as pm
with pm.Model() as model:
    alpha = pm.Normal('alpha', mu=0, sd=1)

这对我有用：

Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24) 
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.environ['MKL_THREADING_LAYER'] = 'GNU'
>>> import pymc3 as pm
>>> with pm.Model() as model:
...     alpha = pm.Normal('alpha', mu=0, sd=1)
... 
>>>