[Numeric] Announcement: Fast Fourier transform with comfort-fftw

[Henning Thielemann]

I have released:
    https://hackage.haskell.org/package/fftw-ffi
    https://hackage.haskell.org/package/comfort-fftw

This is an alternative to the 'fft' package (based on 'carray' and 
'ix-shapable').

The package comfort-fftw is based on comfort-array and uses Cyclic and 
Half Spectrum shapes. The Cyclic shape allows you to access the (n-1)-th 
element also by index (-1). This reflects the cyclic interpretation of 
data implied by the discrete Fourier transform. The Half Spectrum shape 
greatly simplifies working with the spectrum of real data, both of even 
and odd length, and reduces the danger of mistakes. The bindings use 
distinct array shapes for the four kinds of both cosine and sine 
transformation and thus ensure, that you use the right one for back 
transformation.

Two examples may demonstrate its usage:

https://hackage.haskell.org/package/align-audio
    Find relative displacement of two recordings of the same music.

https://hackage.haskell.org/package/sound-collage
    Assemble a mosaic of sound snippets according to a target music recording.