Simple fixed-point iteration method

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

[Dimitris Kalogiros]

Dear John

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

[John Smith]

Thank you for the answer, but I checked this and I really have the file in the working directory.

In fact, I have another function in the directory, which runs with no problems...

[Dimitris Kalogiros]

I wonder , what is the calling program.

If you don't mind , could you provide it ?

[John Smith]

I am not sure, what I have done, but it is working fine now. ¯\_(ツ)_/¯

Anyway, thank you for your time.

> I wonder , what is the calling program.

It might have been the problem. I guess the function and the file have to share the name, right?(I mean, if I code a function F, then it has to be saved as file F.m.)

[Dimitris Kalogiros]

Hm hm, I don't know if it is necessary , but I always follow this rule.

Answer 2

[Ishita Sharma]

f(x)=x^2 - x -1 =0

Answer 3

[emmanuel john Lavarias]

1. Solve one real root of ex−2x−5=0ex−2x−5=0 with x0=−2x0=−2 using the Fixed-Point Iteration Method accurate to four decimal places.

Answer 4

[Ahteshamul Hoque Tareq]

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 5

[Tsega'ab]

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