我在一个包里面有一个cython扩展，结构如下：
packagename
├── MANIFEST.in
├── packagename
│ ├── __init__.py
│ ├── packagename.py
│ ├── subpackage1
│ │ ├── __init__.py
│ │ ├── subpackage1.py
│ │ └── cythonExt1.pyx
│ ├── subpackage2
│ │ ├── __init__.py
│ │ ├── subpackage2.py
│ │ └── cythonExt2.pyx
│ └── VERSION
├── requirements.txt
└── setup.py
当我尝试在cythonExt2.pyx中添加一行导入numpy我得到以下错误：
-------------------------------------------------------------
SystemError Traceback (most recent call last)
<ipython-input-5-5c4ef4d8efd3> in <module>()
1 # Calling Functions of Interest
----> 2 import pacakge.subpackage2 as thingy
3 import numpy as np
4 import matplotlib.pyplot as plt
/home/user/anaconda2/envs/python3/lib/python3.5/site-packages/pacakage-0.0.3-py3.5-linux-x86_64.egg/package/__init__.py in <module>()
18
19 # the following line imports all the functions from package.py
---> 20 from .package import *
21 import package.subpackage1
22 import package.subpackage2
/home/user/anaconda2/envs/python3/lib/python3.5/site-packages/package-0.0.3-py3.5-linux-x86_64.egg/package/package.py in <module>()
1 from package.subpackage1 import thingy1
----> 2 from package.subpackage2 import thingy2
3 import numpy as _np
4 from multiprocessing import Pool as _Pool
/home/user/anaconda2/envs/python3/lib/python3.5/site-packages/package-0.0.3-py3.5-linux-x86_64.egg/package/subpackage2/subpackage2.py in <module>()
3 import os
----> 4 from cythonExt2 import solve as solve_cython
5 from frange import frange
6
/home/user/anaconda2/envs/python3/lib/python3.5/site-packages/package-0.0.3-py3.5-linux-x86_64.egg/package/subpackage2/cythonExt2.pyx in init package.subpackge2.cythonExt2 (package/subpackage2/cythonExt2.c:6158)()
1 cimport numpy
----> 2 import numpy
3 cimport cython
4
5 def get_z_n(n, z):
SystemError: Parent module '' not loaded, cannot perform relative import
如果我只是cimport numpy这工作，我可以访问numpy C API，但我无法导入我需要解决特定问题的numpy python函数 .
为什么会这样，我该如何解决？
我想知道我的安装文件是否存在导致此操作无效的问题 . 我的setup.py文件的cython部分是这样的：
from setuptools import setup
from setuptools.extension import Extension
from Cython.Build import cythonize
from Cython.Build import build_ext
extensions = [Extension(
name="cythonExt1",
sources=["package/subpackage1/cythonExt1.pyx"],
include_dirs=[numpy.get_include()],
),
Extension(
name="cythonExt2",
sources=["package/subpackage2/cythonExt2.pyx"],
include_dirs=[numpy.get_include()],
)
]
setup(name='package',
...
include_package_data=True,
packages=['package',
'package.subpackage1',
'package.subpackage2',
],
ext_modules = cythonize(extensions),
install_requires=requirements,
)
1 回答
问题是这个setup.py文件和工作流程没有正确包含numpy . 我通过更改它来修复此问题，使得cython扩展在其自己的目录中进行cython化，并将其自己的setup.py文件转换为.c文件，然后将该文件作为C扩展添加到软件包的setup.py文件中 . 这也有一个好处，即安装模块的人不需要cython，因为您可以使用包分发生成的.c文件 .
我在我的github here上创建了这个完整但简单的示例 .