func4p1.asv

来自「数值分析最常用的四十种算法」· ASV 代码 · 共 11 行

x=linspace(.5,3.0,6)
y=[1.75,2.45,3.81,4.80,7.00,8.60]
p=polyfit(x,y,3)
xx=linspace(0.5,3,100)
yy=polyval(p,xx)
plot(xx,yy,'-')
f=polyval(p,x)
disp(abs(norm(y,inf)-norm(f,inf)))
%the residue is (defined by infinite norm on those vector) : 0.0950
%如提高为用三次多项式拟合，residue= 0.0517,更为精确；
%can also see the figure