zuixiao.m

最小二乘法的matlab语言

x=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];
y=[24.948 24.768 24.804 24.732 24.840 24.768 24.732 24.840 25.056 25.020 24.696 24.876 24.840 24.948 24.948 24.984 25.236 24.876 25.128 25.020 25.128];
n=2;
p=polyfit(x, y, n);
xi=linspace(0,20);
z=polyval(p, xi);
plot(x, y, ' o ' , x, y, xi, z, ' : ' )
xlabel(' x '), ylabel(' y=f(x) '), title(' Second Order Curve Fitting ')
%syms xi;
%diff(z)

%pp=polyfit(x, y, 10) ;
%format short e%change display format
%pp.'%display polynomial coefficients as a column
%zz=polyval(pp, xi);%evaluate 10th order polynomial
%plot(x, y, ' o ' , xi, z, ' : ' , xi, zz)%plot data
%xlabel(' x '),ylabel(' y=f(x) '),title(' 2nd and 10th Order curve Fitting ')