怎样能更好的编写拉格朗日差值多项式程序

lujiangyue

谢谢

jackdong

Lagrange 插值多项式

功能：求基于N+1个点的拉格朗日多项式

function [C,L]=lagran(X,Y)

% input   - X is a vector that contains a list of abscissas

%           - Y is a vector that contains a list of ordinates

% output  - C is a matrix that contains the coefficients of the lagrange interpolatory polynomial

                 - L is a matrix that contains the lagrange coefficients  polynomial

w=length(X);

n=w-1;

L=zeros(w,w);

for k=1:n+1

    V=1;

    for j=1:n+1

        if k~=j

           V=conv(V,poly(X(j)))/(X(k)-X(j));

        end

    end

    L(k,:)=V;

end

C=Y*L;