Calling function inside function input
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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.
采纳的回答
Walter Roberson
2022-10-8
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
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