In article <mike-3101951555580001 at morpheus.lif.icnet.uk>, mike at bison.lif.icnet.uk (Mike Mitchell) writes:
> I have recently come across the use of FFT to analyse the periodic
> distribution of charge and apolar amino acids in proteins. The paper
> does not explain how it was done!!
>> Has anybody done this sort of analysis before? If so, how did you do
> it, what sort of software did you use, and is there a ftp site where
> copies could be obtained?
This topic is discussed in the "Numerical Recipes ... The Art of
Scientific Computing" books by Press, Flannery, Teukolsky and
Vetterling. I have a copy of "Numerical Recipes in C" (ISBN
0-521-35465-x). Chapter 12 is titled Fourier Transform Spectral
Methods with section 12.2 containing a good explanation of the FFT.
For a less mathematical discussion, I remember Scientific American had
an article on the Fourier Transform a few years ago (1988, 89?).
I believe you can get working FFT code from netlib. To get an index,
send an email message containing only "send index" to netlib at ornl.gov.