FFT Lib?

[dsimcha]

== Quote from Fawzi Mohamed (fawzi at gmx.ch)'s article
> otherwise, as I already said http://www.netlib.org/fftpack/fft.c is
> public domain, has reasonable performance, and supports all sizes.
> It might not be the always beautiful, but it is stable and works well...
> Fawzi

Yeah, I just looked at this code.  The problem is that I wouldn't do a straight,
mechanical port to D, I'd D-ify the code a little while I was at it (such as
making it work on generic random access ranges if it's an out of place transform,
making real-only inputs vs. complex inputs DRYer with templates, etc.).  Since
this code seems to have been straight-up translated from FORTRAN, it scores about
a -2 the readability scale, from 1 to 10.  In other words, I would probably be
able to translate it and make it run, but even the slightest modification would be
near impossible.