化学信号除非前面有pyp的导入，否则不导入

Question

这太奇怪了。在每次导入时，这会以两种不同的方式失败

>>> import scipy.signal
Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    import scipy.signal
  File "C:\Users\ewwieser\AppData\Local\Programs\Python\Python35\lib\site-packages\scipy\signal\__init__.py", line 282, in <module>
    from .bsplines import *
  File "C:\Users\ewwieser\AppData\Local\Programs\Python\Python35\lib\site-packages\scipy\signal\bsplines.py", line 12, in <module>
    from scipy.special import comb, gamma
  File "C:\Users\ewwieser\AppData\Local\Programs\Python\Python35\lib\site-packages\scipy\special\__init__.py", line 627, in <module>
    from ._ufuncs import *
  File "scipy\special\_ufuncs.pyx", line 1, in init scipy.special._ufuncs (scipy\special\_ufuncs.c:26242)
ImportError: DLL load failed: The specified module could not be found.
>>> import matplotlib.pyplot
>>> import scipy.signal
Traceback (most recent call last):
  File "<pyshell#7>", line 1, in <module>
    import scipy.signal
  File "C:\Users\ewwieser\AppData\Local\Programs\Python\Python35\lib\site-packages\scipy\signal\__init__.py", line 282, in <module>
    from .bsplines import *
  File "C:\Users\ewwieser\AppData\Local\Programs\Python\Python35\lib\site-packages\scipy\signal\bsplines.py", line 12, in <module>
    from scipy.special import comb, gamma
  File "C:\Users\ewwieser\AppData\Local\Programs\Python\Python35\lib\site-packages\scipy\special\__init__.py", line 629, in <module>
    from .basic import *
  File "C:\Users\ewwieser\AppData\Local\Programs\Python\Python35\lib\site-packages\scipy\special\basic.py", line 14, in <module>
    from ._ufuncs import (ellipkm1, mathieu_a, mathieu_b, iv, jv, gamma, psi, zeta,
ImportError: cannot import name 'ellipkm1'

然而，这一切都很好（在一个新鲜的壳里）：

^{pr2}$

我的设置是：

• windows上的Python 3.5.1 x64
• Numpy 1.11.0（从^{}安装）
• Scipy 0.17.1（从^{}安装）
• Matplotlib 1.5.1（直接与pip install matplotlib一起安装）

为什么进口互相依赖？怎么可能呢？在