How to convert matrix to a stack of diagonal matrices based on every row?

Question

I have a matrix:

A = [1 1 1
     2 2 2
     3 3 3]

Is there a vectorized way of obtaining:

B = [1 0 0 
     0 1 0
     0 0          


        

Answer 1

Edit: I guess thewaywewalk's benchmark leaves me only with a readability argument ;)

Edit using Beaker's suggestion:

data = [1 1 1
     2 2 2
     3 3 3];
sz = size(data);
z = zeros(sz(1)*sz(2), sz(2));
for i = 1 : sz(1)
    z((i-1)*sz(2)+1:i*sz(2), :) = diag(data(i, :));
end