edward源代码中class Normal的位置在哪里？

Question

在使用edward时，我们总是使用from edward.models import Normal，但是我在github

中没有找到Normal的声明

谁能告诉我它在哪里

Answer 1

它们在 edward/models/random_variables.py 中定义。

你像这样导入 Normal class：

from edward.models import Normal

这建议查看 edward/models/__init__.py，其中有这一行：

from edward.models.random_variables import *

查看 edward/models/random_variables.py 我们发现 this code:

from edward.models.random_variable import RandomVariable as _RandomVariable
from tensorflow.contrib import distributions as _distributions

# Automatically generate random variable classes from classes in
# tf.contrib.distributions.
_globals = globals()
for _name in sorted(dir(_distributions)):
  _candidate = getattr(_distributions, _name)
  if (_inspect.isclass(_candidate) and
          _candidate != _distributions.Distribution and
          issubclass(_candidate, _distributions.Distribution)):

    # to use _candidate's docstring, must write a new __init__ method
    def __init__(self, *args, **kwargs):
      _RandomVariable.__init__(self, *args, **kwargs)
    __init__.__doc__ = _candidate.__init__.__doc__
    _params = {'__doc__': _candidate.__doc__,
               '__init__': __init__}
    _globals[_name] = type(_name, (_RandomVariable, _candidate), _params)

del _candidate

这通过 tensorflow.contrib.distributions 模块寻找从 tensorflow.contrib.distributions.Distribution 派生的 classes（忽略其他属性，例如模块的 __file__ 成员，或基Distribution class 本身）。对于每一个，它都会进行一些修改（这只会影响生成的文档）然后执行这个关键行：

_globals[_name] = type(_name, (_RandomVariable, _candidate), _params)

type() built-in function creates a new type i.e. declares a new class. The second parameter is the list of base classes, which here is edward's RandomVariable class and the TensorFlow random variable class. Earlier it defined _globals to be globals()，这是一个返回模块变量字典的内置函数。因此，如果您感兴趣，上面的行等同于以下内容：

from edward.models.random_variable import RandomVariable as EdRandVar
from tensorflow.contrib.distributions import Normal as TfNormal
Normal = type("Normal", (EdRandVar, TfNormal), {...})

这又等同于此（如果您忽略文档字符串内容）：

from edward.models.random_variable import RandomVariable as EdRandVar
from tensorflow.contrib.distributions import Normal as TfNormal
class Normal(EdRandVar, TfNormal):
    pass

edward源代码中class Normal的位置在哪里？

where is the location of class Normal in edward's source code?

tensorflow

edward