Question

I have a matrix X e.g = [a b; c d; e f].

I need to create another matrix listing the index positions and values of the matrix.

e.g. The output is E = [ 1 1 a ; 1 2 b ; 2 1 c ; 2 2 d ; 3 1 e ; 3 2 f ]

I have been trying to use a double for loop but even if it did work, that sounds like a bad idea.

So can anyone has a better idea to perform above task?

Answer 1

Here is the dumbest thing I could think of (Assuming that a,b,c,d,e,f are all scalars)

x = [1 2;3 4;5 6];
[i,j]=ind2sub(size(transpose(x)), 1:numel(x));
[j(:) i(:) reshape(transpose(x),[],1)]

However, I have a feeling that there might be an answer that is more elegant.