mypolyfit.m

matlab的二次拟合程序源码与大家分享！直接是M文件！

function mypolyfit(x,y)
A = zeros(2);
[n,A(1,1)] = size(x);
n = A(1,1);
x1 = x';
x2 = x.^2;
x3 = x2';
A(1,2) = x*x1;
A(2,1) = x*x1;
A(2,2) = x2*x3;
y1 = y';
t(1:n) = 1;
t1 = t';
f(1) = y*t1;
f(2) = y*x1.^2;
f = f';
j = A\f
y2 = j(1) + j(2)*x.^2;
plot(x,y2,'g');
t = j(1) + j(2)*x.^2 - y
t1 = t';
sqrt(t*t1)