[Numpy-discussion] need help building a numpy extension that uses fftpack on windows

Robert Kern robert.kern@gmail....
Thu Jun 2 14:33:47 CDT 2011

On Thu, Jun 2, 2011 at 14:07, Ralf Gommers <ralf.gommers@googlemail.com> wrote:
> On Wed, Jun 1, 2011 at 5:45 PM, martin smith <gmane@blindgoat.org> wrote:
>> I have a bit of code that performs multi-taper power spectra using numpy
>> and a C extension module.  The C portion consists of an interface file
>> and a python-unaware computational file.  The latter invokes fftpack.
>> The straightforward setup.py appended below works fine on Linux.  On
>> Windows using MinGW it's not so good. I first created a libpython27.a
>> file following instructions on the web.  The C code now compiles but
>> fails to link since there is no fftpack_lite.so on Windows.  I can't
>> find an fftpack_lite.dll (or even the source for fftpack_lite) and don't
>> know where to turn.
> Python dll's on Windows have a .pyd extension, there should be a
> fftpack_lite.pyd file. But you should be able to just leave off the
> extension, so it does the right thing on any platform.
> Also, the way you specified library_dirs doesn't work if numpy is not in
> site-packages, better to use something like:
>      library_dirs = [os.path.join(numpy.__path__[0], 'fft')]

That said, there is no good cross-platform way to link against other
Python extension modules. Please do not try. You will have to include
a copy of the FFTPACK code in your own extension module.

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
  -- Umberto Eco

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