A weird blank matrix....

Hello all, I am new to matlab and trying to figure out the following code. As you can see I have commented out the line in question and marked it. Apart from preallocation, I fail to see the point in the code Xu as it doesn't appear to affect the final result.

Many thanks

   hold on
title('Plot of uniform random numbers')
Xu = [];
for i=1:nn
x = rand(mm,2) %create a random 2 column matrix of numbers
%Xu = [Xu;x] %what does this do? 
plot(x(:,1),x(:,2),'*');
end

Answer 1

[Walter Roberson]

It does not affect the final plotted result. It does, however, keep a record of all of the x values that were generated, in case you want them later.