Calculating the between-column squared correlations

I want to use the Latin hypercube sample function (lhsdesign). In the examples provided in the documentation the quality of the generated design is measured by calculating the sum of between-column aquared correlations,

rng default % For reproducibility
X= lhsdesign(10,4); % X is a 10-by-4 design matrix.
y= corr(X);
(sum(y(:).^2)-4)/2 % the 4 subtracted to remove the ones on the diagonal of y.

Why was the sum of the squared correlations divided by 2 ?

Thanks

Answer 1

[Matt J]

I would guess it's account for the symmetry of the y matrix ... so that off-diagonal terms will not be double counted.

[Amin Kassab-Bachi]

True! I didn't notice at all! Thanks a lot for taking the time.