syms does not work on my matlab

I have installed Symbolic Math Toolbox and Simulink for my Matlab but when I try to use syms on my program it doesn't work.

"Execution of script syms as a function is not supported:" shows up

At first I thought I installed it wrong but sym works perfectly fine....

Only syms doesn't work....

What is the problem?

Answer 1

[John D'Errico]

Is there a reason why you decided to name a script syms, and then tried to use syms itself? What you did was confuse MATLAB, so that now, when it tried to use the real syms command/function, it sees your script FIRST.

DO NOT NAME YOU OWN FUNCTIONS OR SCRIPTS WITH NAMES THAT ALREADY EXIST. If you do that, then do you see what happens?

To fix this, rename the script you created.

[Seungjun Lee]

clear all
close all
clc
syms a b c x
ff = a*x^2+b*x+c

solve(ff==0,x)

This is the program I used...

I don't think I did anything to confuse matlab...

[Steven Lord]

John suspects that you wrote your own script file syms.m that's taking precedence over the syms function in Symbolic Math Toolbox. To check this, use the which function. What do you see when you run this command?

which -all syms

/MATLAB/toolbox/symbolic/symbolic/syms.m

If you see a file that you've created (not one in a subdirectory of the toolbox directory under matlabroot) try renaming it and running your code again.

But if that's the verbatim error message you received the colon at the end of the message text seems odd.

[Seungjun Lee]

I renamed it just in case and after i tried 'which -all syms' I see

C:\Users\rotom\OneDrive\Seungjun\sy.m

C:\Program Files\MATLAB\R2021b\toolbox\symbolic\symbolic\syms.m % Shadowed

It still doesn't work...

What's %Shadowed?... Maybe this is the problem?...

[Seungjun Lee]

Oh I got it, after I renamed my file I didn't erase my old syms.m file.

Thank you very much!! :)

[Image Analyst]

Please accept this answer to give John credit ("reputation points") for the solution. Thanks in advance. 🙂

[John D'Errico]

Yes. Shadowed is the phrase indicating something else lies in front of the real syms utility. So syms lies in the shadow. Somewhere, we knew that you had done exactly that, as this is the only way you could have had this problem.

[John]

LOL. I just ran into the same problem, named a script with syms.

[John D'Errico]

This is perhap one of the ways new users to MATLAB most frequently aground. And then they get a strange error, because MATLAB becomes completely confused. It has no idea what went wrong. The solution is to get used to the idea of not naming your scripts of functions with names already in use. It becomes a habit that you learn, avoiding that. And from then on, the problem goes away, at least for you.