[Numpy-discussion] help with typemapping a C function to use numpy arrays

Rich E reakinator@gmail....
Thu Jan 8 14:43:35 CST 2009


I am using %includ "sms.h", which is what is wrapping all my
functions.  Without doing this, I have to hand-wrap every function in
the header file!

Is there a way to exclude certain definitions from my c header file
when using %include, so that I can hand wrap them instead?

On Thu, Jan 8, 2009 at 2:13 AM, Egor Zindy <ezindy@gmail.com> wrote:
> Hello Rich,
>
> This is very strange. I got to test my example again, as long as you don't
> do a
> %include "dftmagnitude.h"
> somewhere in the dftmagnitude.i, it's perfectly possible to do a
> %rename (sms_spectrumMag) my_spectrumMag;
> (see dftmagnitude3.zip attached in my previous mail and this one).
>
> So things for you to check:
>   * does the simple dftmagnitude3.zip compile on your system?
>   * what version of SWIG are you using? (I used 1.3.36 provided with cygwin)
>   * do you have a %include statement somewhere in your own .i file?
>
> Matthieu, if you read this, there's a complete example provided in
> dftmagnitude3.zip.
>   * Wrapped function sms_spectrumMag in dftmagnitude.c and .h
>   * SWIG wrapper dftmagnitude.i uses %inline and %rename statements
>   * Example uses a modified numpy.i (see the previous mails in the thread).
>   * test example provided in test_dftmagnitude.py
>
> Haven't tested it under Linux, but under winxp/cygwin/mingw32, the following
> works for me (in cygwin):
>
> $ python setup_dftmagnitude.py build -cmingw32 ; mv
> build/lib.win32-2.5/_dftmagnitude.pyd .
> $ python test_dftmagnitude.py
>
> Regards,
> Egor
>
> --
> My Python:
> $ python -i
> Python 2.5.4 (r254:67916, Dec 23 2008, 15:10:54) [MSC v.1310 32 bit (Intel)]
> on win32
>
> My SWIG:
> $ swig -version
>
> SWIG Version 1.3.36
>
> Compiled with g++ [i686-pc-cygwin]
> Please see http://www.swig.org for reporting bugs and further information
>
>
>
>
> On Thu, Jan 8, 2009 at 1:43 AM, Rich E <reakinator@gmail.com> wrote:
>>
>> Here is my example, trying to wrap the function sms_spectrumMag that
>> we have been dealing with:
>>
>> %apply (int DIM1, float* IN_ARRAY1) {(int sizeInArray, float* pInArray)};
>> %apply (int DIM1, float* INPLACE_ARRAY1) {(int sizeOutArray, float*
>> pOutArray)};
>>
>> %inline %{
>>
>>        void my_spectrumMag( int sizeInArray, float *pInArray, int
>> sizeOutArray, float *pOutArray)
>>        {
>>                sms_spectrumMag(sizeOutArray, pInArray, pOutArray);
>>        }
>>
>> %}
>>
>>
>> at this point,  have the new function my_spectrumMag that wraps
>> sms_spectrumMag() and provides arguments that can be typemapped using
>> numpy.i  Now, I don't want to have to call the function
>> my_spectrumMag() in python, I want to use the original name, I would
>> like to call the function as:
>>
>> sms_spectrumMag(numpyArray1, numpyArray2)
>>
>> But, trying to %rename my_spectrumMag to sms_spectrumMag does not
>> work, the original sms_spectrumMag gets called in python instead.
>> Trying to %ignore the original function first as follows removes the
>> sms_spectrumMag completely from the module and I am left with
>> my_spectrumMag:
>>
>> %ignore sms_spectrumMag;
>> %rename (sms_spectrumMag) my_spectrumMag;
>>
>>
>> Do you see my problem?
>>
>>
>> On Wed, Jan 7, 2009 at 8:58 AM, Matthieu Brucher
>> <matthieu.brucher@gmail.com> wrote:
>> > 2009/1/6 Rich E <reakinator@gmail.com>:
>> >> This helped immensely.  I feel like I am getting close to being able
>> >> to accomplish what I would like with SWIG: producing a python module
>> >> that can be very 'python-like', while co-existing with the c library
>> >> that is very 'c-like'.
>> >>
>> >> There is one question still remaining though, is it possible to make
>> >> the wrapped function have the same name still?  Using either
>> >> my_spectrumMag or spectrumMag means I have to create a number of
>> >> inconsistencies between the python module and the c library.  It is
>> >> ideal to ignore (%ignore?) the c sms_spectrumMag and instead use the
>> >> wrapped one, with the same name.  But my attempts at doing this so far
>> >> have not compiled because of name conflictions.
>> >
>> > Ok course you can. The function is renamed only if you say so. Perhaps
>> > can you provide a small example of what doesn't work at the moment ?
>> >
>> >> Thanks for the help, I think you are doing great things with this
>> >> numpy interface/typemaps system.
>> >
>> > Matthieu
>> > --
>> > Information System Engineer, Ph.D.
>> > Website: http://matthieu-brucher.developpez.com/
>> > Blogs: http://matt.eifelle.com and http://blog.developpez.com/?blog=92
>> > LinkedIn: http://www.linkedin.com/in/matthieubrucher
>> > _______________________________________________
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