# -*- org -*-

#+CATEGORY: fft

* Sine and Cosine Transforms from FFTPACK. 

* A simple multidimensional fft.

* Convolutions. This will need different interfaces corresponding to

the type of underlying FFT (radix-2, mixed-radix, radix-2 real,

mixed-radix real). The convolution function should be fft'ed before

being passed, so that the function can be used in a loop.  The main

point of the function being to do the index manipulation for the

multiplication F*G.  Theoretically someone might want to convolve real

and complex data together which could be done but would double the

number of interfaces. It would be reasonable to restrict the

convolutions to real-real and complex-complex.