How can I use repmat function for the following code?

I need to remove the for loop and I want use repmat for this code

Y= zeros(64,64);
load('brain512.mat')
X=data;
Z = imresize(X, [64 64]);
N=64;
m=64;
n=64;
for p=0:N-1
    for q=0:N-1
        for j=0:m-1
            for k=0:n-1
                Y(p+1,q+1) = Y(p+1,q+1)+exp(-2*pi*1i*p*j/m)*exp(-2*pi*1i*q*k/n)*Z(j+1,k+1);
            end
        end
    end
end

[Walter Roberson]

http://www.mathworks.co.uk/matlabcentral/answers/43073-a-guide-to-tags

[Image Analyst]

For some reason you removed all the comments in your code before you posted it (which I'm sure you had, like all good programmers do). So, explain in words what it does.

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Akshay Khadse]

Please do mention the contents of 'brain512.mat'.

[Bhanu Prakash Edukulla]

Hello Akshay, Thanks for commenting, I uploaded the file.

Regards Bhanu