trying to call a function from a function file in a script file

func 

[Stephen23]

"but when I try to run this code the error says "Execution of script afunction as a function is not supported"

Get rid of all code outside of the function definition. Having code outside of the function definition makes it into a script, which will not work. You need to provide FZERO with a function handle, not run a script or call a function:

https://www.mathworks.com/help/matlab/matlab_prog/scripts-and-functions.html

Do not call your function. Provide FZERO with a function handle:

x = fzero(@afunction, [llim ulim],options);

https://www.mathworks.com/help/matlab/matlab_prog/creating-a-function-handle.html

Answer 1

[Muskan]

Hi,

As per my undersatnding the issue is because you named the script "afunction"

Hence when when the script gets to this line:

func = afunction;

As a result, it tries to call "afunction" but cannot, because that is what you called your script.

The way to resolve this issue is to change the name of your script to something else.

You can refer to the following MATLAB Answer for more information: https://www.mathworks.com/matlabcentral/answers/1633265-i-have-this-error-execution-of-script-plot-as-a-function-is-not-supported-c-users-jonathan-e-le

[Olivia]

i've tried renaming the function file to something else but then when I try to call afunciton it says function or variable not recognized :(

[Muskan]

Is it possible for you to share the script in order to help debug?

[Stephen23]

Get rid of all code outside of the function definition! This you should save in an MFILE of the same name:

function y = afunciton(x)
y = exp(cos(x)) - x.^3 + 2*x.^2 + 5*x - 3;
end

And this is how you call it:

llim = -5;
ulim = -1;
options = optimset('Display','iter','TolX',10^-7,'Maxiter',500);
x = fzero(@afunciton, [llim ulim],options)

 
 Func-count    x          f(x)             Procedure
    2              -1      -3.28347        initial
    3        -1.08663       -3.1958        interpolation
    4        -1.08663       -3.1958        bisection
    5        -1.28168      -2.68766        interpolation
    6        -1.28168      -2.68766        interpolation
    7        -1.53453      -1.31264        interpolation
    8        -1.73932      0.461266        interpolation
    9        -1.68607    -0.0601463        interpolation
   10        -1.69221   -0.00220062        interpolation
   11        -1.69244   7.41169e-07        interpolation
   12        -1.69244   7.41169e-07        interpolation
 
Zero found in the interval [-5, -1]

x = -1.6924

Answer 2

[Walter Roberson]

func = @afunction; %trying to make the variable func equivalent to "afunciton", 
% the function I created in the afunction file but it doesn't work :(
llim = -5;
ulim = -1;
options = optimset('Display','iter','TolX',10^-7,'Maxiter',500);
[x] = fzero(func, [llim ulim],options);

However... your afunction is a script rather than a function, and for the purposes of fzero you strictly need to use a function.

My guess is that your afunction.m starts something like

clear all; clc
function z = afunction(x)

That "clear all" at the beginning of it is unnecessary, and makes the code into a script file instead of a function file.