%type myfft
function B=myfft(A)
%i=1:256;j=1:256;
n=length(A);
B=zeros(n);
for u=1:n
    for v=1:n
        for x=1:n
            for y=1:n
               % u=double(u);v=double(v);x=double(x);y=double(y);n=double(n);   
                temp=double(A(x,y));
                a=temp*exp(-j*2*pi*((u-1)*(x-1)+(v-1)*(y-1))/n);
                    B(u,v)=B(u,v)+a;
                end
            end
        end
    end