Charles Vejnar <[EMAIL PROTECTED]> wrote: > Hi, > > Thanks for both suggestions. > > I have indeed tried gmpy. For me, it's not very important to choose between > numpy or gmpy. > > I hope I won't be off topic. But, as I told you before, I have a C library > using "long double" numbers and I would like to be able to use it in Python. > I try to build a module with Swig but I didn't find the C function to use in > the wrapper to have a "numpy.longdouble" (or the equivalent in gmpy). Is it > something possible ?
I'm not a SWIG expert, but I believe you can tell SWIG exactly what C function to use to convert a certain C type to Python; gmpy has a C API for that purpose, and so no doubt does numpy (I'm the author of gmpy, but don't know much about numpy, so I'm just guessing about it). You may have to write a little bit of custom C code for the purpose... and I'm not even sure you'll be able to do that with SWIG specifically for "long double", judging from a document at swig.org which I quote later. I realize that this answer is far from being fully satisfactory:-(. Unfortunately, neither pyrex nor ctypes, which today are probably the two best ways to interface arbitrary C code with Python, have good support for long double, and, as <http://www.swig.org/Doc1.3/SWIG.html> says, "The rarely used datatype of long double is not supported by SWIG":-(. Writing a custom C extension to wrap long double for Python would not be hard -- essentially, copy Objects/floatobject.c from the Python source distribution and edit it just a wee little bit -- but wouldn't necessarily be sufficient to let you use your desired C library, since you'd still have to somehow tell SWIG (or whatever other C/Python interfacing approach) to use it... Alex -- http://mail.python.org/mailman/listinfo/python-list
