Calling functions

I have written a MATLAB code say myfun.m which first line is

function y = myfun(x)

Now I want to call it in another code I am writing. I have 2 values x1 and x2 and I want my present code to compare myfun(x1) and myfun(x2) such that if myfun(x1) > myfun(x2) then it does something.

I tried writing

if (myfun(x1)>myfun(x2))
...

But MATLAB says

??? Output argument "y" (and maybe others) not assigned during
call to "/Users/user/Documents/MATLAB/compare.m>myfun".

What should I do?

Thanks.

Answer 1

[the cyclist]

This works for me:

x1 = 2;
x2 = 1;

if myfun(x1) > myfun(x2)
    disp('myfun(x1) is greater than myfun(x2)')
else
    disp('myfun(x1) is not greater than myfun(x2)')
end

where myfun.m is:

function y = myfun(x)
    y = x.^2;
end

Answer 2

[Jan]

The error message means, that for some branchs of the program myfun the output y is not defined. You can use the debugger to let Martlab stop, when the problem occurs:

dbstop if error

Then you can investigate the current calling stack and values of the variables.