digui.m

线行方程组的Gauss Jacobi 及一个简单的自适应算法

function [ v ] = digui(f,a,b,ep)


h  = b-a;
x  = [a b];
y  = feval(f,x);
So = sum(y)*h/2;

xx = [a (a+b)/2 b];
ww = [1 4 1];
yy = feval(f,xx).*ww;
S = sum(yy)*h/6;


if abs(S-So)<ep || (b-a) <ep
    v = S;
else
    v = digui(f,a,(a+b)/2,ep) + digui(f,(a+b)/2,b,ep);
end