python局部加权回归

import numpy as np
import matplotlib.pyplot as plt
x=[[400],[450],[484],[500],[510],[525],[540],[549],[558],[590],[610],[640],[680],[750],[900]]
y=[[80],[89],[92],[102],[121],[160],[180],[189],[199],[203],[247],[250],[259],[289],[356]]
plt.plot(x,y,'ks')
end=[[0],[0]]
for i in range(len(x)):
    x[i].insert(0,1)
xx=np.mat(x)#转成矩阵
yy=np.mat(y)
end=np.mat([0,0])
end=end.T#矩阵转逆
k=2#加权参数
weight=np.mat(np.eye((len(x))))
for j in range(len(x)):
    diff=x[6]-xx[j,:]
    weight[j,j]=np.exp(diff*diff.T/(-2*k**2))
end=(xx.T*(weight*xx)).I*(xx.T*(weight*yy))
end=end.getA().tolist()#矩阵转成列表
print(end)
X=[400,900]
Y=[]
Y.append(end[0][0]+end[1][0]*X[0])
Y.append(end[0][0]+end[1][0]*X[1])
plt.plot(X,Y,'g-')
plt.show()