simpson.m

梯形与simpson求积公式 分别是梯形,simpson,和3/8simpson的matlab代码,计算的区间被划分成为了又2到256个,精度逐渐增加.

function I = simpson(fun,a,b,npanel)

n = 2*npanel + 1;
h = (b-a)/(n-1);
x = a:h:b;
f = feval(fun,x);

I = (h/3) * ( f(1) + 4*sum(f(2:2:n-1)) + 2*sum(f(3:2:n-2)) + f(n) );
%              f(a)    f_even             f_odd              f(b)