On Tue, Oct 25, 2016 at 3:25 AM, Dieter Werthmüller <dieter@werthmuller.org> wrote:

I agree, probably the best would be to use the already existing FFTPACK
and the already existing complex gamma function, which would mean only
one file, fftlog.f, has to be added.

In this regard, it might be best to first ask if there is sufficient
interest for a logarithmic FFT, as you point out Joshua, before
investing more time. Any opinions? For anyone interested I list the
website of the original FFTLog again:
http://casa.colorado.edu/~ajsh/FFTLog

I haven't come across a use case for this myself, but the original paper [1] is highly cited and the citation come from a range of fields. The one fftlog.f file doesn't look worse than the average Fortran file, so this will likely be okay to maintain. So I'm fine with adding this feature.

Ralf

[1] http://www.sciencedirect.com/science/article/pii/0021999178901079