[R] a question about fft ( fast fourier transform)

lma5@ncsu.edu lma5 at ncsu.edu
Tue Jul 26 21:18:06 CEST 2005

Dear listers

 In R, if I have a sequence x(t), t=1,...N, fft(x) is actually giving us
sum(x(t)exp(-i*omega*t)) at fourier frequency omega= 2*pi*i/N,

The question is if I want to calculate sum(x(t)exp(-i*2*omega*t)), how can
I do it?
thanks a lot!

liyun (Lauren) Ma
Dept of Statistics
North Carolina State University

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