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Poisson equation/zero padding and duplicating Green function

  1. Apr 6, 2015 #1

    I need to solve the Poisson equation in gravitational case (for galaxy dynamics) with Green's function by applying Fast Fourier Transform.

    I don't understand the method used for an isolated system from (Hockney & Eastwood 1981); it says :

    I have 2 questions:

    * Why we duplicate the Green function ? It seems like one wants to make it periodic but why ?

    * Why do we "zero padding" on distribution charges ? Is it because the Green function is duplicated and stored on 2N points ?

    Thanks in advance
    Last edited: Apr 6, 2015
  2. jcsd
  3. Apr 12, 2015 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
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