liner.m

利用牛顿、拉格朗日、三次样条及线性插值方法拟合数据

function L =Liner(x)
X=0:10;
X=-5+X;
l=0:10;
L=0;
if x>=X(1)&&x<=X(2)
    l(1)=(x-X(2))/(X(1)-X(2));
elseif x>=X(2)&&x<=X(11)
    l(1)=0;
end
for i=2:10
    if x>=X(i-1)&&x<=X(i)
        l(i)=(x-X(i-1))/(X(i)-X(i-1));
    elseif x>=X(i)&&x<=X(i+1)
        l(i)=(x-X(i+1))/(X(i)-X(i+1));
    else
        l(i)=0;
    end
end
if x>=X(10)&&x<=X(11)
    l(11)=(x-X(10))/(X(11)-X(10));
else
    l(11)=0;
end
M=0:10;
syms m
r=1/(1+m^2);
for i=1:11
M(i)=subs(r,'m',X(i));
L=L+M(i)*l(i);
end