[R] Layout of Fourier frequencies

[Timothy H. Keitt]

I'm doing convolutions in the frequency domain and need to know the
layout of the Fourier modes returned by fft. (This is leading up to a
more involved question about moment generating functions, but I need to
know if I've got this part correct first.)

I think in 1D the pattern is:

0 1 2 3 -2 1 (even)
0 1 2 3 -3 2 1 (odd)

In 2D is it simply (for a square matrix):

0 1 2 -1 (horizontal)
0 1 2 -1
0 1 2 -1
0 1 2 -1

and the above transposed for the vertical? Thanks.

Tim

-- 
Timothy H. Keitt
Department of Ecology and Evolution
State University of New York at Stony Brook
Stony Brook, New York 11794 USA
Phone: 631-632-1101, FAX: 631-632-7626
http://life.bio.sunysb.edu/ee/keitt/
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