Pairwise comparision matrix considering a permutation

With the following code

A=[2 3;

4 7;

5 4;

2 1];

idx = nchoosek(1:size(A, 1), 2);

B = A(idx(:, 1), :) - A(idx(:, 2), :)

I get:

B = 6×2

-2 -4

-3 -1

0 2

-1 3

2 6

3 3

But, how can I get a comparision for a rows permutation? Not combination.

Answer 1

[Hyeokjin Jho]

A=[2    3; 
   4    7; 
   5    4; 
   2    1];

len = size(A,1);
idx(:,1) = repelem(1:len,len);
idx(:,2) = repmat(1:len,1,4);

B   = A(idx(:, 1), :) - A(idx(:, 2), :)

[Dan Ibarra]

Thank you.