% Function Subprogram sdis3.m
%
% Solves the dispersion parts of the coupled differential equations
% using a fast-Fourier-transform.

function y = sdis5(a,f,g,e,aa,dk,h)

[hh ns] = size(f);
hs = ns/2;
A1 = fft(a,ns);
A = [A1(hs+1 : ns) A1(1 : hs)];
ff = 2 * pi * f;
%xx = i * (g*ff + e*ff.*ff) + (aa - i*dk);  %MISTAKE till 2002.2.19
xx = i * (g*ff + e*ff.*ff) + (aa + i*dk);
y1 = exp(-xx*h/2) .*A;

yy = [y1(hs+1:ns) y1(1:hs)];
y = ifft(yy, ns);

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