function r=bisection(f,a,b,varargin)
%BISECTION Root finding, bisection method.
%   X=BISECTION(F,A,B) attempts to find the solution of F(X)=0 in the
%   interval [A,B] such that F(A)*F(B) < 0. 
%
%   X=BISECTION(F,A,B,P1,P2,...) passes the parameters P1,P2,... to F.
%
%   See also NEWTON, SECANT, IQI.

%   Francisco J. Beron-Vera
%   $Revision: 1.1 $  $Date: 2006/09/19 13:28:03 $

if f(a,varargin{:})*f(b,varargin{:})>=0
   error('F(A)*F(B) must be negative.')
end
for k=1:54
   r=(a+b)/2;
   if f(a,varargin{:})*f(r,varargin{:})<0
      b=r;
   else
      a=r;
   end
   %disp(sprintf('%2i %bx',[k r]))
   disp([sprintf('%2i',k) ' ' num2bin(r)])
en