让distutils在正确的位置查找numpy头文件

Question

在我的装置中，numpy的arrayobject.h位于…/site-packages/numpy/core/include/numpy/arrayobject.h。我写了一个使用numpy的简单Cython脚本：

cimport numpy as np

def say_hello_to(name):
    print("Hello %s!" % name)

我也有以下distutils setup.py（从Cython user guide复制）：

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

ext_modules = [Extension("hello", ["hello.pyx"])]

setup(
  name = 'Hello world app',
  cmdclass = {'build_ext': build_ext},
  ext_modules = ext_modules
)

当我尝试使用python setup.py build_ext --inplace构建时，Cython尝试执行以下操作：

gcc -fno-strict-aliasing -Wno-long-double -no-cpp-precomp -mno-fused-madd \
-fno-common -dynamic -DNDEBUG -g -Os -Wall -Wstrict-prototypes -DMACOSX \
-I/usr/include/ffi -DENABLE_DTRACE -arch i386 -arch ppc -pipe \
-I/System/Library/Frameworks/Python.framework/Versions/2.5/include/python2.5 \
-c hello.c -o build/temp.macosx-10.5-i386-2.5/hello.o

可以预见，这无法找到arrayobject.h。如何让distutils使用numpy包含文件的正确位置（不让用户定义$ CFLAGS）？

Answer 1

使用numpy.get_include()：

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext
import numpy as np                           # <---- New line

ext_modules = [Extension("hello", ["hello.pyx"])]

setup(
  name = 'Hello world app',
  cmdclass = {'build_ext': build_ext},
  include_dirs = [np.get_include()],         # <---- New line
  ext_modules = ext_modules
)

Answer 2

@ vebjorn-ljosa给出的答案是正确的，但与install_requires=['numpy']一起使用时会引起问题。在这种情况下，你的setup.py需要导入numpy，如果你尝试pip install你的项目而不先运行pip install numpy，将导致错误。

如果您的项目依赖于numpy，并且您希望将numpy作为依赖项自动安装，则只有在实际构建扩展时才需要设置include_dirs。你可以通过继承build_ext来做到这一点：

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

class CustomBuildExtCommand(build_ext):
    """build_ext command for use when numpy headers are needed."""
    def run(self):

        # Import numpy here, only when headers are needed
        import numpy

        # Add numpy headers to include_dirs
        self.include_dirs.append(numpy.get_include())

        # Call original build_ext command
        build_ext.run(self)

ext_modules = [Extension("hello", ["hello.pyx"])]

setup(
  name = 'Hello world app',
  cmdclass = {'build_ext': CustomBuildExtCommand},
  install_requires=['numpy'],
  ext_modules = ext_modules
)

您可以使用类似的技巧将cython添加为自动安装的依赖项：

from distutils.core import setup
from distutils.extension import Extension

try:
    from Cython.setuptools import build_ext
except:
    # If we couldn't import Cython, use the normal setuptools
    # and look for a pre-compiled .c file instead of a .pyx file
    from setuptools.command.build_ext import build_ext
    ext_modules = [Extension("hello", ["hello.c"])]
else:
    # If we successfully imported Cython, look for a .pyx file
    ext_modules = [Extension("hello", ["hello.pyx"])]

class CustomBuildExtCommand(build_ext):
    """build_ext command for use when numpy headers are needed."""
    def run(self):

        # Import numpy here, only when headers are needed
        import numpy

        # Add numpy headers to include_dirs
        self.include_dirs.append(numpy.get_include())

        # Call original build_ext command
        build_ext.run(self)

setup(
  name = 'Hello world app',
  cmdclass = {'build_ext': CustomBuildExtCommand},
  install_requires=['cython', 'numpy'],
  ext_modules = ext_modules
)

注意：这些方法仅适用于pip install .。它们不适用于python setup.py install或python setup.py develop，因为在这些命令中导致依赖项安装在项目之后，而不是之前。

Answer 3

对于没有使用Cython的人来说，如果你只是从distutils.command.build_ext而不是Cython导入build_ext，那么稍微修改R_Beagrie的解决方案就没有那种依赖性。

from distutils.core import setup
from distutils.extension import Extension
from distutils.command.build_ext import build_ext

class CustomBuildExtCommand(build_ext):
    """build_ext command for use when numpy headers are needed."""
    def run(self):

        # Import numpy here, only when headers are needed
        import numpy

        # Add numpy headers to include_dirs
        self.include_dirs.append(numpy.get_include())

        # Call original build_ext command
        build_ext.run(self)

ext_modules = [Extension("hello", ["hello.c"])]

setup(
  name = 'Hello world app',
  cmdclass = {'build_ext': CustomBuildExtCommand},
  install_requires=['numpy'],
  ext_modules = ext_modules
)