p.m

比较三次样条插值和拉格朗日插值多项式对runge函数插值的效果并作图解释

function v=p(x, y, u)
n=length(x);
v=zeros(size(u));
for k=1:n
    w=ones(size(u));
    for j=[1:k-1 k+1:n]
        w=(u-x(j))./(x(k)-x(j)).*w;
    end
    v=v+w*y(k);
end