[Numpy-discussion] [EXTERNAL] Fwd: numpy.i and std::complex

Bill Spotz wfspotz at sandia.gov
Mon Oct 27 12:13:05 EDT 2014


Supporting std::complex<> was just low enough priority for me that I decided to wait until someone expressed interest ... and now, many years later, someone finally has.

I would be happy to include this into numpy.i, but I would like to see some tests in the numpy repository demonstrating that it works.  These could be relatively short and simple, and since float and double are the only scalar data types that I could foresee supporting, there would not be a need for testing the large numbers of data types that the other tests cover.  

I would also want to protect the references to C++ objects with '#ifdef __cplusplus', but that is easy enough.


On Oct 27, 2014, at 9:06 AM, Glen Mabey <gmabey at swri.org> wrote:

> Hello,
> I was very excited to learn about numpy.i for easy numpy+swigification of C code -- it's really handy.
> Knowing that swig wraps C code, I wasn't too surprised that there was the issue with complex data types (as described at http://docs.scipy.org/doc/numpy/reference/swig.interface-file.html#other-common-types-complex), but still it was pretty disappointing because most of my data is complex, and I'm invoking methods written to use C++'s std::complex class.
> After quite a bit of puzzling and not much help from previous mailing list posts, I created this very brief but very useful file, which I call numpy_std_complex.i --
> /* -*- C -*-  (not really, but good for syntax highlighting) */
> %include "numpy.i"
> %include <std_complex.i>
> %numpy_typemaps(std::complex<float>,  NPY_CFLOAT , int)
> %numpy_typemaps(std::complex<double>, NPY_CDOUBLE, int)
> #endif /* SWIGPYTHON */
> I'd really like for this to be included alongside numpy.i -- but maybe I overestimate the number of numpy users who use complex data (let your voice be heard!) and who also end up using std::complex in C++ land.
> Or if anyone wants to improve upon this usage I would be very happy to hear about what I'm missing.
> I'm sure there's a documented way to submit this file to the git repo, but let me simultaneously ask whether list subscribers think this is worthwhile and ask someone to add+push it for me …
> Thanks,
> Glen Mabey
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** Bill Spotz                                              **
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