from an email by Wayne Torrey [WAPHYLZ(AT)aol.com]:
I happened upon your FFT page and noticed that you have a generalized radix
FFT algorithm attributed to Glassman (listed as unknown). I don't know if it
is of any interest to you, but I can cite a reference by him which describes
the algorithm. It appeared in the IEEE Transactions on Computers in the
February, 1970 issue. It was written by J. A. Glassman who is listed as
working at Hughes Aircraft in Canoga Park California. The title of the paper
is "A Generalization of the Fast Fourier Transform" and describes the
calculation of a n-point FFT where n is not restricted to be a power of 2.
He provides a Fortran listing of the algorithm as well as the mathematical
development of it.
I used this algorithm and a modification of the code to implement a piece of
test equipment back in the early 1970's when I was working for IBM. I have
never seen another paper by Glassman, but I recently came across a reference
to his generalized radix algorithm which provides an alternate (and perhaps
simpler) derivation. Here is the reference:
W. E. Ferguson, Jr., "A simple derivation of Glassman general-n fast
Fourier transform," Comput. and Math. with Appls., vol. 8, no. 6, pp.
401-411, 1982.
Also, in Report AD-A083 811, NTIS, Dec. 1979.
Wayne Torrey
Thanks go to for Wayne Torrey for this piece of information !