MATLAB: Simple fixed-point iteration method

Question

My task is to implement (simple) fixed-point interation.

So far, I've got the following and I keep receiving error Undefined function 'fixedpoint' for input arguments of type 'function_handle'.

(I'm new in Matlab, so there may be both syntactical or semantical errors…)

function [ x ] = fixedpoint(g,I,y,tol,m)
% input: g, I, y, tol, max
% g - function
% I - interval
% y - starting point
% tol - tolerance (error)
% m - maximal number of iterations
% x - approximate solution
a=I(1);b=I(2);
if(y<a | y>b)
    error('The starting iteration does not lie in I.')
end
x=y;
gx=g(y);
while(abs(x-gx)>tol & m>0)
    if(gx<a | gx>b)
        error('The point g(x) does not lie in I.')
    end
    y=x;
    x=g(y);
    m=m-1;
end

Answer 1

Dear John

Put your function into the same folder with the program (m-file) that calls it.