Question

I want to use the matlab function roots in a function.

But it doesn’t work. I have no idea how to solve that problem.

Here is the function:

function [ roots , poles ] = pr_calc( num , den )
%PR_CALC Summary of this function goes here
%   Detailed explanation goes here


poles=roots([den]);
roots=roots([num]);

end

And this is the error message:

??? At compilation, "roots" was determined to be
a variable and this
 variable is uninitialized.  "roots" is also a
 function name and previous versions of MATLAB
 would have called the function.
 However, MATLAB 7 forbids the use of the same
 name in the same
 context as both a function and a variable.

Error in ==> pr_calc at 6
poles=roots([den]);

Answer 1

I think matlab is telling you everything you need to know, actually. You have defined a variable called “roots” as the return value from your function, but “roots” is already a function, so you are not allowed to use the same name. Try this:

function [ myroots , poles ] = pr_calc( num , den )
%PR_CALC Summary of this function goes here
%   Detailed explanation goes here


poles=roots([den]);
myroots=roots([num]);

end