Ranking rows in a matrix without changing order of elements in rows

Hi there

I have a 4x4 matrix of 1s and 0s, eg A = [1 0 0 1 0; 0 1 1 1 1; 1 0 1 1 0; 0 0 0 1 0]

In my code I am calling each row, so A(1,:),A(2,:) and so forth.

How can I rank each row according to how many 1's are in the row? Without changing the order of the elements in that row. So ideally I would like:

B = [0 1 1 1 1; 1 0 1 1 0; 1 0 0 1 0; 0 0 0 1 0]

I thought about summing each row and then sorting them, but then how would I be able to continue referencing A(1,:), A(2,:)?

Background: I am trying to code a simple genetic algorithm and so I need to crossover the rows that have the most 1's.

Thanks

Answer 1

[MHN]

A = [1 0 0 1 0; 0 1 1 1 1; 1 0 1 1 0; 0 0 0 1 0]
B = sum(A')';
[m,n] = sort(B);

now A(n(1),:) shows the raw with the least 1's, A(n(2),:) shows the next raw with the least 1's, and so on. By this method you havent changed the order of A's raw and you also now where is the row with the smallest number of 1's and so on.

[J OBrien]

Thank you so very much