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comparison four.m @ 832:5573913a0949 feature/burgers1d

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Merged with default, and updated +scheme/Burgers1D accordingly
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Tue, 11 Sep 2018 15:58:35 +0200
parents f6ada1719420
children
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831:d0934d1143b7 832:5573913a0949
1 % four returns the fourier transform u_hat of the function u and the frequencies w
2 function [w, u_hat] = four(x, u)
3 u_hat = fft(u);
4
5 N = length(x);
6 L = x(end) - x(1);
7
8 k = shift_k(0:N-1);
9
10 u_hat = fftshift(u_hat);
11
12 dw = 2*pi/L;
13 w = dw*k;
14 end
15
16 function k_shifted = shift_k(k)
17 N = length(k);
18 k_shifted = [-floor(N/2):-1, 0, 1:ceil(N/2)-1];
19 end