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Re: Fourier transform

  • To: mathgroup at
  • Subject: [mg13928] Re: [mg13923] Fourier transform
  • From: "Jens-Peer Kuska" <kuska at>
  • Date: Tue, 8 Sep 1998 02:52:28 -0400
  • Sender: owner-wri-mathgroup at

Hi Andrea,

Fourier[] implements a numerical fast fourier transform. That means that
the data passed to Fourier[] are  the function values f(t) on the
interval t in [0,2Pi) with constant increment. The data are assumed to
be periodic in t with period 2Pi.

Assume You have a solution ndsol={y[t]->InterpolatingFunction[<>][t]}
fun=y[t] /. ndsol;

You get Your data set and can use


to make the transformation.
For other time intervals You need a proper scaleing of the t-variable.

Hope that helps

-----Original Message-----
From: Andrea Cherubini <Andrea.Cherubini at> To:
mathgroup at
Subject: [mg13928] [mg13923] Fourier transform

>how can I do the Fourier Transform of NDSolve results?
>Thanks, Andrea

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