d2f.m

用matlab实现Romberg积分

function [y,e]=d2f(x,h)
y0=0.78333;
if h==0.001
    y1=0.78270;y2=0.78395;
elseif h==0.002
    y1=0.78208;y2=0.78457;
elseif h==0.005
    y1=0.78021;y2=0.78643;
elseif h==0.010
    y1=0.77707;y2=0.78950;
elseif h==0.020
    y1=0.77074;y2=0.79560;
elseif h==0.050
    y1=0.75128;y2=0.81342;
else
    y1=0.71736;y2=0.84147;
end                   
y=(y2+y1-2*y0)/h.^2;
e=abs(y+0.78333);