gusucode.com > 《精通matlab 7》包括配套光盘 > 配套光盘里的程序附件/Ex-16/Ex1604.m

    %例16-4 spline函数和pchip函数
x = -3:3; 
y = [-1 -1 -1 0 1 1 1]; 
t = -3:.01:3;
p = pchip(x,y,t);
ppol=spline(x,y)
s=ppval(ppol,t);
plot(x,y,'o',t,p,'-',t,s,'-.')	%画图，如图16-6
legend('data','pchip','spline','Location','SouthEast')	%在图像的右下方标注