MATLAB: Indexing back into an array the same size as one that was just sorted

Question

I'm trying to first sort each row of a 3X3 array. And then take the subscripts of the two largest numbers in each row and pull them out.

So,

A = magic(3);
[~, IDX] = sort(A, 2, 'descend');

And then use IDX to pull out the largest 2 numbers in each row in array A, leaving me with and array sized 3,2.

Answer 1

FirstN = 2;
B = A(sub2ind(size(A), repmat((1:size(A,1)).',1,FirstN), IDX(:,1:FirstN)));