[R] fft help
mkondrin at hppi.troitsk.ru
Wed Mar 12 01:55:54 CET 2003
Kenneth Cabrera wrote:
> Hi R-users:
> I want to know if there is an easy way to obtain a Fourier Transform form
> a vector or an array (just like fft does), but with a more density base.
> I mean, if I have a vector of 512 of length, I want the Fourier
> Transform to
> be 1024, or 2048, etc, in length (de u domain). Or should I modify the
> fft C code to do that?
There is no point in it. Procedure you are proposed to do is just sort
of smoothing - it adds no new information. You see - fourier transform
is just definition of new coordinates in functional space. If you have
512 points - this is dimension of this space and coordinate basis can
have only 512 vectors. Any other vectors (additional points in fourier
transform) are linear combinations of them.
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