Sorting a matrix using it's index

Hello Matlab users,

My problem is a simple one. But I've had no luck finding a solution on the forums, possibly due to not being able to describe my problem sufficiently.

I want to use the sort function, on matrix A:

A = [2,5,4,1,6; 
    9,8,3,7,0]

If I use the following function to sort A by rows:

[Asort,idA] = sort(A,2)

I get the expected result:

Asort = [1,2,4,5,6;
         0,3,7,8,9]

and the corresponding index matrix:

idA = [4,1,3,2,5; 
       5,3,4,2,1]

Next, I wish to use this index on another matrix B. But first, I can check by using it again on A:

Asort2 = A(idA)

This method doesn't work as it's now indexing using the entire matrix and not on a row-by-row basis. To get around this, I have had to implement the following for loop to work on each row:

for ii = 1:size(A,1)
    Asort2(ii,:) = A(ii,idA(ii,:));
end

This is not the most elegant solution. Is there a preferred/more concise way of doing this operation?

Thanks for your help!

Answer 1

[madhan ravi]

 Asort2 = A(sub2ind(size(A), repmat((1:size(A,1)).', 1, size(A,2)), idA))

Answer 2

[Bruno Luong]

[Asort,idA] = sort(A,2)

m = size(A,1);
ilinA = (idA-1)*m+(1:m)';
Asort3 = A(ilinA) % get back Asort