bisection method - can't see error in code

I am unable to pin point the error in my code of my funtion for the bisection method, any help would be greatly appreciated

function [rootx]=bisect(fhandle,a,b,epsilon)

rootx=[];
Fa=fhandle(a);
Fb=fhandle(b);
m=((b-a)/2);
Fm=fhandle(m);

while abs(m)>epsilon ; 

      if Fb*Fm <0
          a=m
      else
          b=m
      end
  end
  return m=((a+b)/2)
      end
  rootx

[Matt J]

Not pasting in the error messages or other symptoms of malfunction makes it hard for us to pinpoint, too.

[Mahesha MG]

http://numericalcomputation.blogspot.in/2012/07/matlab-bisection-method.html

Answer 1

[James Tursa]

1) Google "bisection method"

2) Go to the 1st Wiki link

3) Look at the pseudo-code posted there

4) Compare that to your code to discover your errors, paying special attention to what Matt J said about not updating your variables within your loop.

Answer 2

[Matt J]

One idea:

m=((b-a)/2);

Shouldn't it be + instead of - ?

Also, you don't assign anything to rootx in the code except the initialization rootx=[]. Also, throughout the loop, you are not updating, m, Fb, or Fm.

Answer 3

[Babak]

In the while loop

 while abs(m)>epsilon ;

    if Fb*Fm <0
        a=m
    else
        b=m
    end
 end

you are not changing m and you are trying to check the abs(m)

I think you meant

 m=a

and

 m=b

instead...