How do I do this summation equation in MATLAB

Hi! I'm a beginner MATLAB user and I'm trying to implement this summation equation in MATLAB but I'm not really sure how?

I'm used to other programming languages so I'd likely just use a nested for loop but I'm not sure if that's the best approach with MATLAB.

Equation is here:

where u is a pair and is a 128x128 matrix

My current best guess is to use nested for loops as such:

eta = zeros(1, N); % 1xN column vector to store answer
for row = 1:N   %u1 is a "row"
    tmp = 0;
    for col = 1:N/2 % u2 is the "column" and only goes to N/2 (specified elsewhere)
        tmp = tmp + abs(Y(row, col))^2; 
    end
    eta(1, row) = tmp / N;
end

Answer 1

[Matt J]

Looks like you could simply do it in one line with,

eta=vecnorm(Y(:,1:N/2),2,2).^2/N ;

[Brian]

Is that effectively the same as the way I have it done currently? Just more succint?

[Torsten]

N = 4;
Y = rand(N) + 1i*rand(N);
eta = zeros(1, N); % 1xN column vector to store answer
for row = 1:N   %u1 is a "row"
    tmp = 0;
    for col = 1:N/2 % u2 is the "column" and only goes to N/2 (specified elsewhere)
        tmp = tmp + abs(Y(row, col))^2; 
    end
    eta(1, row) = tmp / N;
end
eta

eta = 1×4

0.0859 0.2986 0.3841 0.3292

eta=vecnorm(Y(:,1:N/2),2,2).^2/N;
eta

eta = 4×1

0.0859 0.2986 0.3841 0.3292