See
You are running a function file. Apparently when calling a function you have to pass input arguments. See the example below:
x=1:10; % define the input before passing in
D = samplle(x)
function D = samplle(x) % function definition
D=x.^2;
end
Note : In versions prior to 2016b function definition have to be saved in a separate file containing the same name of a function but in 2016b or later a script file contain a function definition at the very end.
