SWIG is a program that automatically generates code to interface Python (and many other languages) with C/C++. If you plan to create lasting software libraries to be accessed from Python and C it is quite a robust way to do so. Essentially, you feed it header files, compile your code and the code generated by swig as a shared library, then import the functions like you would a normal python module.
If all you need is to make some numerical code run faster it may be more of a learning curve then you bargain for. Perhaps trying NumPy is more appropriate. http://numpy.scipy.org/ -Brian On Wed, Apr 9, 2008 at 2:44 PM, Paul Anton Letnes <[EMAIL PROTECTED]> wrote: > Hi, and thanks. > > > However, being a newbie, I now have to ask: What is SWIG? I have heard the > name before, but haven't understood what it is, why I need it, or similar. > Could you please supply some hints? > > > -Paul > > > Den 9. april. 2008 kl. 22.22 skrev Brian Cole: > > > > > > > > > > We use the following SWIG (www.swig.org) typemap to perform such > operations: > > > > %typemap(in) (int argc, char **argv) { > > if (!PySequence_Check($input)) { > > PyErr_SetString(PyExc_ValueError,"Expected a sequence"); > > return NULL; > > } > > $1 = PySequence_Length($input); > > $2 = (char**)alloca($1*sizeof(char*)); > > for (Py_ssize_t i = 0; i < $1; ++i) { > > PyObject *o = PySequence_GetItem($input, i); > > $2[i] = PyString_AsString(o); > > } > > } > > > > That one works for mapping a python sequence (such as a list) into the > > argc, argv arguments commonly passed into main. > > > > -Brian > > > > On Wed, Apr 9, 2008 at 2:13 PM, Paul Anton Letnes > > <[EMAIL PROTECTED]> wrote: > > > > > Hello etc. > > > > > > > > > I am a "scientific" user of Python, and hence have to write some > performance > > > critical algorithms. Right now, I am learning Python, so this is a > "newbie" > > > question. > > > > > > I would like to wrap some heavy C functions inside Python, specifically > a > > > wavelet transform. I am beginning to become aquainted with the functions > > > PyArg_ParseTuple() and Py_BuildValue(). However, I am unable to figure > out > > > how to pass Python list -> C function or C array -> return value in > Python. > > > I manage to build and run the C function, print to screen, pass string > as > > > argument, return an int, etc. The thing which is missing is the magic > > > array/list... > > > > > > > > > Thanks in advance! I fart in your general direction. > > > Paul. > > > -- > > > http://mail.python.org/mailman/listinfo/python-list > > > > > > > > -- > > > > http://mail.python.org/mailman/listinfo/python-list > > > > -- http://mail.python.org/mailman/listinfo/python-list
