自写程序，拉格朗日插值且给出插值多项式的系数

beyondhxf

有时候只是想知道 拉格朗日插值 后的多项式系数具体是多少，这个程序就能实现！

function coef=LagrangeInterpolation(xx,yy)
%get the ploynimial coefficients of Lagrange interpolation.
%input is a set of sample points
%output is the coefficients of Lagrange interpolation.
syms x
y=0;
%start to implement the Lagrange interpolation
for i=1:length(xx)
    p=1;
    for j=1:length(xx)
        if(j~=i)
            p=p*(xx(j)-x)/(xx(j)-xx(i));
        end
    end
    y=y+p*yy(i);
end
%get the coefficients of polynimial
coef=sym2poly(y);
return