Number of elements mismatch.

Hi everyone, I have a dimension issue: I have a Simulink Matlab Function block that has a [3x1] vector of values called pd as its input. This vector should turn into a [6x1] vector called pdot by adding three zeros to every element. Basically just resizing from to it sounds rather simple but I can't get it to work. The code that I use in my Simulink function block is shown below.     function pdot = fcn(pd) pdot = zeros(6,1); temp = zeros(6,1); for i = 1:length(pd) pdot(i) = temp(i) + [pd(i); 0; 0; 0]; end end