Z=srule(f,a0,b0,tol0)

function Z=srule(f,a0,b0,tol0)

%Input   - f is the integrand input as a string 'f'
%        - a0 and b0 are upper and lower limits of integration
%        - tol0 is the tolerance
% Output - Z is a 1 x 6 vector [a0 b0 S S2 err tol1] 

% NUMERICAL METHODS: MATLAB Programs
%(c) 1999 by John H. Mathews and Kurtis D. Fink
%To accompany the textbook:
%NUMERICAL METHODS Using MATLAB,
%by John H. Mathews and Kurtis D. Fink
%ISBN 0-13-270042-5, (c) 1999
%PRENTICE HALL, INC.
%Upper Saddle River, NJ 07458

h=(b0-a0)/2;
C=zeros(1,3);
C=feval(f,[a0 (a0+b0)/2 b0]);
S=h*(C(1)+4*C(2)+C(3))/3;
S2=S;
tol1=tol0;
err=tol0;

Z=[a0 b0 S S2 err tol1];