intgausshermite.m

数值积分的几种算法

function I = IntGaussHermite(f,n,AK,XK)
if(n<6 && nargin == 2)
    AK = 0;
    XK = 0;
else
    I=sum(AK.*subs(sym(f),findsym(sym(f)),XK));
end

switch n
    case 2,
        I=0.886227*(subs(sym(f),findsym(sym(f)),-0.707107)+...
            subs(sym(f),findsym(sym(f)),0.707107));
        
    case 3,
        I=1.181636*subs(sym(f),findsym(sym(f)),0)+...
            0.295409*(subs(sym(f),findsym(sym(f)),1.224745)+...
            subs(sym(f),findsym(sym(f)),-1.224745));
        
    case 4,
        I=0.544444*(subs(sym(f),findsym(sym(f)),0.524648)+...
            subs(sym(f),findsym(sym(f)),-0.524648))+...
            0.100000*(subs(sym(f),findsym(sym(f)),1.650680)+...
            subs(sym(f),findsym(sym(f)),-1.650680));
           
    case 5,
        I=0.945309*subs(sym(f),findsym(sym(f)),0)+...
            0.393619*(subs(sym(f),findsym(sym(f)),0.958572)+...
            subs(sym(f),findsym(sym(f)),-0.958572))+...
            0.199532*(subs(sym(f),findsym(sym(f)),2.020183)+...
            subs(sym(f),findsym(sym(f)),-2.020183));  
end