View Full Version : Mixing C++ and Python for Simulations

February 16th, 2013, 05:58 PM

I write programs in C++ using the eigen and mpfr libraries to run simulations of physical systems. Which means my programs do mathematical computations with arbitrary precision arithmetic.

What I am thinking is to use Python to handle everything that is not the computations: Data Input and Output (which is simply writing files), etc.

I have tried to read a bit around, but due to my inexperience with Python (I never used it up to now), I would like to have some expert opinion on the topic. Am I going to have problems? If so, which ones? Etc. etc.

My doubts are born from these points:

I sometime use arbitrary precision type from the library mpfr. I know python has no problem with this type of numbers, but passing them to a C function and receiving them as a return value from them... can these be problematic?
I always use matrices. Specifically, I use the eigen Matrix types (dynamic dimension), if I want to use Python to handle all the file I/O I need to pass these specific types as return value (actually a pointer to one, or an array, of them)
If I do all the I/O in Python, I am going to have Python calling C++ calling Python. I suppose this shouldn't be too much of a problem, but still... is it going to be so? I only mixed C, C++ and Fortran up to now, and no one of them is an interpreted language

Is there anyone that already tried to do something like this? Do you have any suggestion? I.e. use cpickle for handling the data I/O, etc.

Thank you!

February 17th, 2013, 12:56 AM
Have you read this? (http://docs.python.org/2/extending/extending.html) I think creating a python extension module is the only real option here. I believe you will find answers to all of your doubts after you've created a simple extension module or two.

The problem is, python modules are generally written in C. Writing them in C++ is possible, but it's not as easy. Check out PyCXX on sourceforge.

I found this tutorial helpful. (http://www.tutorialspoint.com/python/python_further_extensions.htm)