rearrange the G matrix

Dear

I plot each point in freq. domain and I did ifft.

f=0:1/1024:1;
t=0:1/1024:1;
a=10;
for i=1:1025
if f(i)>=25/1024 && f(i)<=100/1024
    v(i)=a;
else
    v(i)=0;
end
end

figure;
plot(f,v);

for i=1:1025
    G(i)=0;
    for j=1:1025
        G(i)=v(j).*cos(i*j*2*pi/1025)+G(i);
    end
end

figure;
plot(t,G)

Now I would like to rearrange the G matrix so that the last half of points are put as the first half and the first half as the last half (i.e. the biggest point is now in the middle.

regards

Dhafer

Answer 1

[Azzi Abdelmalek]

add this code

 n=floor(size(G,2)/2)
 if n==size(G,2)/2
 out(1:n)=G(n+1:end);out(n+1:2*n)=G(1:n)
 else
    out(1:n)=G(n+2:end);
    out(n+1:2*n+1)=G(1:n+1);
 end
 figure;plot(t,out)

Note: in your case length(G)=1025 is odd, i added a test when it's even

Answer 2

[Walter Roberson]

fftshift() ?

Answer 3

[Andrei Bobrov]

n = numel(G);
k = floor(n/2);
p = ceil(n/2)+~rem(n,2);
G([1:k,p:end]) = G([p:end,1:k]);