[Numpy-discussion] BSD C port of FFTPACK incl. bluestein algorithm

[Robert Kern]

On Fri, Nov 18, 2011 at 11:19, Dag Sverre Seljebotn
<d.s.seljebotn at astro.uio.no> wrote:
> I've been in touch with Martin Reinecke, author of the libpsht code for
> spherical harmonic transforms, about licensing issues.
>
> libpsht itself will remain under the GPL, but he is likely to release
> his C port of FFTPACK under BSD in the near future, as it is based on
> the public domain FFTPACK.
>
> I'm grateful for this change for my own purposes (allows releasing my
> own competing SHT library under the BSD) -- but it could perhaps be
> useful for NumPy or SciPy as well, depending on how complete the port
> is? E.g., perhaps make numpy.fft more complete (is the
> numpy.fft/scipy.fftpack split simply because of the Fortran dependency?).

It used to be the case that scipy.fftpack allowed one to build against
multiple different, usually faster, FFT libraries like FFTW. I think
we have backed away from that since the cost of maintaining the build
configuration for all of those different backends was so high. It's
worth noting that numpy.fft is already using a C translation of
FFTPACK. I'm not sure what the differences are between this
translation and Martin's.

-- 
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