Question

在我的安装中，numpy的arrayobject.h位于.../site-packages/numpy/core/include/numpy/arrayobject.h。我编写了一个使用numpy的微不足道的Cython脚本：

cimport numpy as np

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

我还有以下的 distutils setup.py（从Cython 用户指南复制）：

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会尝试执行以下操作:

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

可以预见的是，这种方法无法找到arrayobject.h。我该如何使distutils使用正确的numpy包含文件位置（而不需用户定义$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"],
                                  include_dirs=[get_numpy_include()])]   # <---- New argument

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

Answer 2

@vebjorn-ljosa 给出的答案是正确的，但与 install_requires=[ numpy ] 结合使用时会导致问题。在这种情况下，您的 setup.py 需要导入 numpy，如果您尝试在没有运行 pip install numpy 的情况下 pip install 项目，则会导致错误。

如果您的项目依赖于numpy，并且希望numpy作为依赖自动安装，您需要在实际构建扩展时设置include_dirs。您可以通过子类化build_ext来实现这一点：

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
)

并且,你可以使用类似的骗子,作为自动安装的扶养手段,增加cy:

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 .。这些方法不适用于 python setup.py install 或 python setup.py develop，因为这些命令会在您的项目之后安装依赖项，而不是之前。

Answer 3

对于不使用 Cython 的任何人，一个轻微修改 R_Beagrie 的解决方案，而不依赖它的方法是，如果您只是从 distutils.command.build_ext 导入 build_ext。

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
)

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