python高性能扩展工具-cython教程1快速入门

Cython不仅仅是一种编程语言。它的起源可以追溯到SAGE数学软件包，它用于提高数学计算性能，例如涉及矩阵的计算。更一般地说，我倾向于将Cython视为SWIG的替代品，为本机代码生成非常好的Python绑定。

SWIG是最早和最好之一，用于生成多种语言的绑定的工具。 Cython仅限Python代码。

通过生成语言绑定来处理遗留软件的很好方式，对C / C ++编写的遗留应用程序，用Python添加新功能。

第一章将专注于使用Cython的核心概念

• 安装Cython
• Hello World
• 使用distutils
• Python调用C函数
• 类型转换

安装

Linux及Mac：

pip install Cython

Linux发行版本：

$ yum install cython
# will work on Fedora and Centos
$ apt-get install cython # will work on Debian based systems.

Windows的安装参考：https://github.com/cython/cython/wiki/InstallingOnWindows

Hello World!

helloworld.pyx

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Author:    xurongzhong#126.com 
# CreateDate: 2018-9-20
# 技术支持qq群： 144081101 591302926 567351477 钉钉免费群：21745728
print("Hello World from cython!")

Makefile

all:
    cython -3 -o helloworld.c helloworld.pyx
    gcc -g -O2 -fpic -c helloworld.c -o helloworld.o `python3-config --cflags`
    gcc -g -O2 -shared -o helloworld.so helloworld.o `python3-config --libs`
clean:
    rm -rf *.c *.o *.so build

执行

$ make
cython -3 -o helloworld.c helloworld.pyx
gcc -g -O2 -fpic -c helloworld.c -o helloworld.o `python3-config --cflags`
gcc -g -O2 -shared -o helloworld.so helloworld.o `python3-config --libs`
$ python
Python 3.6.5 |Anaconda, Inc.| (default, Apr 29 2018, 16:14:56) 
[GCC 7.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import helloworld
Hello World from cython!

image.png

使用distutils编译

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Author:    xurongzhong#126.com 
# CreateDate: 2018-9-20
# 技术支持qq群： 144081101 591302926 567351477 钉钉免费群：21745728
from distutils.core import setup
from Cython.Build import cythonize

setup(
    ext_modules = cythonize("helloworld.pyx")
)

执行

$ python setup.py build_ext --inplace
running build_ext
building 'helloworld' extension
gcc -pthread -B /usr/local/anaconda/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/usr/local/anaconda/include/python3.6m -c helloworld.c -o build/temp.linux-x86_64-3.6/helloworld.o
gcc -pthread -shared -B /usr/local/anaconda/compiler_compat -L/usr/local/anaconda/lib -Wl,-rpath=/usr/local/anaconda/lib -Wl,--no-as-needed -Wl,--sysroot=/ build/temp.linux-x86_64-3.6/helloworld.o -o /home/andrew/code/cython-book/chapter1/helloworld/helloworld.cpython-36m-x86_64-linux-gnu.so
$ python
Python 3.6.5 |Anaconda, Inc.| (default, Apr 29 2018, 16:14:56) 
[GCC 7.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import helloworld
Hello World from cython!

参考资料：官方快速入门

此处如果不添加 --inplace，则编译在默认目录

$ python setup.py build_ext
running build_ext
building 'helloworld' extension
gcc -pthread -B /usr/local/anaconda/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/usr/local/anaconda/include/python3.6m -c helloworld.c -o build/temp.linux-x86_64-3.6/helloworld.o
gcc -pthread -shared -B /usr/local/anaconda/compiler_compat -L/usr/local/anaconda/lib -Wl,-rpath=/usr/local/anaconda/lib -Wl,--no-as-needed -Wl,--sysroot=/ build/temp.linux-x86_64-3.6/helloworld.o -o build/lib.linux-x86_64-3.6/helloworld.cpython-36m-x86_64-linux-gnu.so

在root下面执行python3 setup.py install则会安装为系统库

# python3 setup.py build_ext
running build_ext
# python3 setup.py install
running install
running build
running build_ext
running install_lib
copying build/lib.linux-x86_64-3.6/helloworld.cpython-36m-x86_64-linux-gnu.so -> /usr/local/anaconda/lib/python3.6/site-packages
running install_egg_info
Writing /usr/local/anaconda/lib/python3.6/site-packages/UNKNOWN-0.0.0-py3.6.egg-info

Python调用C函数

AddFunction.c

#include <stdio.h>

int AddFunction(int x, int y) {
    printf("look we are within your c code!!\n");
    return x + y;
}

AddFunction.h

#ifndef __ADDFUNCTION_H__
#define __ADDFUNCTION_H__

extern int AddFunction(int, int);

#endif //__ADDFUNCTION_H__

PyAddFunction.pyx

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Author:    xurongzhong#126.com 
# CreateDate: 2018-9-20
# 技术支持qq群： 144081101 591302926 567351477 钉钉免费群：21745728
cdef extern from "AddFunction.h":
    cdef int AddFunction(int, int)

def Add(a, b):
    return AddFunction(a, b)

执行

$ make
cython -3 PyAddFunction.pyx
gcc -g -O2 -fpic -c PyAddFunction.c -o PyAddFunction.o `python3-config --includes`
gcc -g -O2 -fpic -c AddFunction.c -o AddFunction.o
gcc -g -O2 -shared -o PyAddFunction.so AddFunction.o PyAddFunction.o `python3-config --libs`
$ python
Python 3.6.5 |Anaconda, Inc.| (default, Apr 29 2018, 16:14:56) 
[GCC 7.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from PyAddFunction import Add
>>> Add(1,2)
look we are within your c code!!
3

参考资料

• 本文涉及的python测试开发库 谢谢点赞！
• 本文代码地址
• 本文相关书籍下载