function yi=New_Int(x,y,xi)
n=length(x);
m=length(y);
if n~=m
    error('The lengths of X and Y must be equal');
    return;
end
Y=zeros(n);
Y(:,1)=y';
for k=1:n-1]
    if abs(x(i+k)-x(i))<eps
        error('the DATA is error');
        return;
    end
    Y(i,k+1)=(Y(i+1,k)-Y(i,k))/(x(i+k)-x(i));
end
end
yi=0;
for i=1:n
    z=1;
    for k=1:i-1
        z=z*(xi-x(k));
    end
    yi=yi+Y(1,i)*z;
end