function M=myifft(D)
n=length(D);
M=zeros(n);
for x=1:n
    for y=1:n
        for u=1:n
            for v=1:n
                a=(1/n^2)*(D(u,v)*exp(j*2*pi*((u-1)*(x-1)/n+(v-1)*(y-1)/n)));
                M(x,y)=M(x,y)+a;
            end
        end
    end
end