Numerical Analysis/Bisection Method MATLAB Code
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The following is taken from the Ohio University Math 344 Course Page. The program mybisect.m finds roots using the Bisection Method.
function [x e] = mybisect(f,a,b,n)
% function [x e] = mybisect(f,a,b,n)
% Does n iterations of the bisection method for a function f
% Inputs: f -- an inline function
% a,b -- left and right edges of the interval
% n -- the number of bisections to do.
% Outputs: x -- the estimated solution of f(x) = 0
% e -- an upper bound on the error
format long
c = f(a); d = f(b);
if c*d > 0.0
error('Function has same sign at both endpoints.')
end
disp(' x y')
for i = 1:n
x = (a + b)/2;
y = f(x);
disp([ x y])
if y == 0.0 % solved the equation exactly
e = 0;
break % jumps out of the for loop
end
if c*y < 0
b=x;
else
a=x;
end
end
e = (b-a)/2;