Doing the wrapping in an object oriented way is difficult, and maybe
not that useful. This does not prevent the API exposed to python to be
OO, of course.
I have some difficulties to do this in an automated way...
I'm trying now to make a derived object from my function, without templates and, I'm hoping so, with a correct interface
i.e. double + 2*int to save make the conversions with numpy arrays.
> That works great for C then, not that well for C++...
Well, this is an inherent problem of C++ when you try to use it from
other languages, but let's not start this (again :) ),
:D
The example shows basic wrapping, and some facilities provided by
numpy to help. Again, ctype is pretty efficient as long as you do not
need to do convertion. If you call it thousand of times, it will be
slow, but this is more or less inherent to python (function calls are
nowhere near as fast as in a compiled language, at least for now).
It's for optimization, so the function will be called several hundreds of times, I suppose, and I tried porting the whole function to Python, but I'm not sure that the Python version behaves like the C++ version - the results are not identic, so... -, thus the wrapping.
SWIG may be better in your case because it is aware of C++ classes,
and is *compiling* an extension, whereas ctypes does not compile
anything. This means that you do not have to care about binary
interfaces problemes between foreign object codes. SWIG parses a prett
good deal of C++, and is aware of classes (template is another matter,
obviously). numpy sources contain swig code to process automatically
numpy arrays (that is convert C representation of a numpy array to a
simple C array and vice et versa), if I remember correctly.
Yes, I will try to use this solution, I have trouble figuring how passing the output numpy array, Bill Baxter asked the same question today, at exactly the same time ;) Well, I saw on the docs that such arrays must be passed to the function, and already allocated, and that is a problem for me...
There is also boost.python, but I don't know if its situation towards
numpy array has changed (eg there was some code lying around to
represent numpy arrays in C++).
That will be my next quest during the summer ;)
If I were you, and if there are only a few classes and a few member
functions, I would try the C wrapper called from python first.