lagran.m

研一刚上完数值分析

function y=lagran(x0,y0,x)
n=length(x0);
m=length(x);
for i=1:m
   z=x(i);
   s=0.0;
   for k=1:n
       p=1.0;
       for j=1:n
           if j~=k
               p=p*(z-x0(j))/(x0(k)-x0(j));
           end
       end
       s=s+y0(k)*p;
   end
   y(i)=s;
end