[python] A note when trying to use numpy with Cython

Introduction

What I want to do this time is ctypedef numpy.float64_t DOUBLE_t I want to define it as. To do this You need to do cimport numpy. I want to do these two ctypedef and cimport.

• I can't read English I did it while looking at the English document, so it may be wrong. If you don't want to see an error in the middle, please see only the last.

The environment looks like this. OS X, Yosemite Cython 0.23.4 Python 3.4.3

I get the following error when compiling cython.

Refer to the Cython 0.23.2 documentation: Building Cython code page and create the following two scripts.

test.pyx

import numpy
cimport numpy
ctypedef numpy.float64_t DOUBLE_t

setup.py

from distutils.core import setup
from Cython.Build import cythonize

setup(
    name = 'test',
    ext_modules = cythonize('test.pyx')
    )

When I use this to run python setup.py build_ext --inplace, I get the following error:

error.

sample.c:250:10: fatal error: 'numpy/arrayobject.h' file not found
#include "numpy/arrayobject.h"
         ^
1 error generated.
error: command 'clang' failed with exit status 1

I got an error saying that the file is missing. It seems that the path is different, so if you look at the site a little earlier, Something like this Cython 0.23.2 documentation: Compilation

Often, Python packages that offer a C-level API provide a way to find the necessary include files, e.g. for NumPy:

include_path = [numpy.get_include()]

It seemed to be common. For the time being, let's put this in setup.py.

setup.py

from distutils.core import setup
from Cython.Build import cythonize
import numpy

setup(
    name = 'test',
    ext_modules = cythonize('test.pyx')
    include_path = [numpy.get_include()]
    )

When I try to use this, I get an error again

error.

Unknown distribution option: 'include_path'

I was told that there is no such option. Looking at stackoverflow and so on, it seems that everyone does not use ʻinclude_path, but uses ʻinclude_dirs. For the time being, try s / include_path / include_dirs.

setup.py

from distutils.core import setup
from Cython.Build import cythonize
import numpy

setup(
    name = 'test',
    ext_modules = cythonize('test.pyx')
    include_dirs = [numpy.get_include()]
    )

When I tried it, it passed (o ・ ω ・ o) I don't know what it is, but it looks like it was done.

Summary

ʻInclude_dirs = [numpy.get_include ()] It sounds good to use. There are few new ones written in Japanese, so if you don't understand English, it can be painful. I compiled it this time, but there were a lot of warnings for ʻunused function, so maybe I have to fix it? (Because it is an unused function, it may be left alone)