Cython code is annotated "Python-like" code which is compiled to C or C++. This is then wrapped in "interface code" which prodcuces "extension modules" that can be used directly in Python.
The C or C++ code use static types and offer lower overhead in control structures and function calls which can in turn greatly speed up performance on native python code.
More detailed descriptions of the installation can be found here. In short, the latest Cython release can easily be installed with the command
pip install cython
Cython also requires a c compiler to be present on the system. This installation will differ depending on what operatin system you are using.
The GNU C Compiler (gcc) should be available by default in e.g. Ubuntu. If not, it can be installed using
sudo apt-get install build-essential
gcc is not available on Windows by default. Instead we can use MinGW which includes a port of the GNU Compiler Collection (GCC), including C, C++, ADA and Fortran compilers.
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Install MinGW from here
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Run the installer. Only the basic package is needed for Cython, but the C++ compiler might be useful as well.
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Add the installation
bindirectory to the Windows PATH variable, e.g.c:\mingw\bin. -
Specify
mingw32as the default compiler of your python installation by creating a file calleddistutils.cfgwith the following information:[build] compiler = mingw32- E.g. default location of the python interpreter:
C:\Users\<user>\AppData\Local\Programs\Python\<version>\Lib\distutils\distutils.cfg
- E.g. Anaconda environment named
cython:C:\Users\<user>\Anaconda3\envs\cython\Lib\distutils\distutils.cfg
- E.g. default location of the python interpreter:
If you want to learn more about the basics of Cython, you can have a look at this tutorial.
A few important keywords to keep in mind are:
def- Ordinary Python functions which can only be called from Pythoncdef- Pure Cython functions which can only be called from Cythoncpdef- C function with a Python wrapper
This repository includes three different example programs with the .py extension for ordinary python modules and .pyx for code that will be used by Cython to compile to C code.
To compile the code, we run the following command:
python setup.py build_ext --inplace
After the build has finished, we can run test.py to see how the execution time of the native python code compares with the compiled Cython code. In many cases it can over a hundred times faster!
python test.py