Python-Extensions with Other Languages¶

Introduction to Example¶

We use a computationally intensive example throughout the course. This allows for comparison of the different extension methods.

Use of Python’s C-API¶

Standard Python is implemented in C and offers a comprehensive API for writing extensions. The basics of this API are taught. A working extension will be developed by hand that can be used by a Python program.

Python Extensions with Pyrex/Cython¶

Pyrex is a special language for writing Python extensions. It has mainly Python syntax with some limitations and some additions that allow for automatic translation into C code suitable to be compiled in an Python extension. Examples are used to show how Pyrex works. The possibilities of incorporating existing C programs are also explained.

Use of DLLs with ctypes¶

The package ctypes allows to access DLLs or shared libraries from Python. It works on the operating systems Windows, Windows CE, Mac OS X, Linux, Solaris, FreeBSD, and OpenBSD. The language in which the DLL is implemented doesn’t matter. The usage of ctypes is introduced with examples. Under Windows Microsoft’s .NET compiler und the mingw (gcc) compiler are used to compile the DLL. The shared library under Linux Linux is compiled with the gcc. One focus is type conversion between Python and the DLL.

Automatic generation of Extensions with SWIG¶

The “Simplified Wrapper and Interface Generator” (SWIG) allows to make C/C++ libraries accessible from 13 different languages. One of them is Python. The way SWIG works is covered using examples in C as well as in C++.

Jython¶

Jython is an implementation of Python in Java. It allows to access Java classes directly. The course covers the basics of Jython programs. Examples for use of existing Java classes as well as self written classes are used.

IronPython¶

IronPython is a implementation of Python in .NET. It allows Access to all .NET features and makes it a first class .NET language right next to C# and Visual Basic. The course introduces IronPython, demonstrates how to use .NET assemblies, and how access self written C# classes.

Use of FORTRAN Subroutines from Python¶

FORTRAN is one of the oldest programming languages but it is still in heavy use for scientific applications due to its high performance. There are many old but well proven numerical libraries that can be used from Python.

The usage of F2PY to connect FORTRAN77 as well as FORTRAN90/95 programs with Python is demonstrated. One focus are object-oriented interfaces to those libraries.