This library is by Patrick Stein.
The array can be any number of dimensions, but each dimension must be a power-of-two in size.
Here is a simple example on a two-dimensional input buffer.
(require :asdf)
(asdf:operate 'asdf:load-op 'fft)
(defparameter *buf* #2A((1 2 3 4)(5 6 7 8)))
(let ((transformed (fft:fft *buf*)))
(fft:ifft transformed))
Here is an example using the a parallelized version that uses pcall which, in turn, uses Bordeaux-Threads:
(require :asdf)
(asdf:operate 'asdf:load-op 'pfft)
(defparameter *buf* #2A((1 2 3 4)(5 6 7 8)))
(let ((transformed (pfft:pfft *buf*)))
(pfft:pifft transformed))
For a more complete description, see the home page.
Mathematics