How to implement an equation containing nested Summations

I am trying to write a matlab code to evaluate an error function given as:

I tried the following line of matlab code but there seems to be some problem with it.

E=0;
for i = 1:n-1
    for j = i+1:n
        for k = 1:n-1
            for l = k+1:n
                E =E + ((t(i,j)*(D(k) - D(l)) - t(k,l)*(D(i)-D(j))))^2;
            end
        end
    end
end

I am not sure whether I have used the for loops correctly. Please advice. Thanks.

[David Goodmanson]

Hi Sarath, it looks all right. There is an unneeded set of outermost parentheses which should not matter.

[Sarath S]

Thank you for the verification. I think the problem was with one of my variables. It's working much better now.