Make sure you are using (curly) braces and not parentheses:

alpha = varargin{1}


“varargin” is a cell array, so you need to use braces to get the contents of each element. Parentheses will only give you back the element as a cell.

Error in ==> main at 19
out=alpha * beta;

I think that the recent introduction of the inputParser object has made things evolve a bit with respect to the nargin approach.
Have you ever thought about creating a video with a demo of inputParser?

You can use num2str to make a number into text. You can have a function output be string if that is what you want.

Doug

I sometimes use “exist” in order to realize variable inputs:

function bla(A,B,D)
if ~exist(’D', ‘var’)
D = 10; % default value
end
…

Here, I did not hard-code the order and number of input arguments. If I ever want to introduce an additional input C before D, like

function bla(A,B,C,D)

I do not have to change anything (except the function calls of course). I think both alternatives have their pros and cons.

Regards
Markus