Calling function inside function input

I've been trying to run a program that finds the root of a function following the bisection method, given an interval (a,b), tolerance level and maximum iterations for the method. I want to be able to run custom functions, but I cannot seem to find a way to figure it out. I don't know if I'm even chasing the right answer.

I have previously stated my custom function as:

function [y]=fun(x)
y=x-sin(x)-1
end

And then ran my main program like this, using the variables:

z=linspace(0,5,1000);funcion=fun(z);a=1;b=3;tol=0.0001;maxiter=5;

function [x,it]=bisecc(funcion,a,b,tol,maxiter)
for it=1:maxiter
    c=(a+b)/2;
    if sign(funcion(a))~=sign(funcion(c))
        b=c;
    else
        a=c;
    end
    if abs(funcion(c))<tol
        break
    end
end

plot(linspace(a,b,length(funcion)),funcion), grid on

x=c;
[x_]=fzero(funcion,(a+b)/2);    
fprintf('x(fzero)=%f',x_)

However, foolish of me, funcion(*whatever*) just indexes from the matrix that I created, and I spent an embarrasing amount of time until I noticed.

What can I do? Thanks in advance.

Answer 1

[Walter Roberson]

z=linspace(0,5,1000);funcion=fun(z);a=1;b=3;tol=0.0001;maxiter=5;

Do not do that. Instead do

a = 0; b = 5;   %to match your linspace
tol = 0.0001;
maxiter = 5;
[x, it] = bisecc(@fun, a, b, tol, maxiter)

and in the function change

plot(linspace(a,b,length(funcion)),funcion), grid on

to

X = linspace(a,b,500);
plot(X, funcion(X)), grid on