vstack leastsquare

import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline
f = np.poly1d([5, 1])
x = np.linspace(0, 10, 30)
y = f(x) + 6*np.random.normal(size=len(x))
plt.plot(x, y,"or")


a=np.vstack([x,np.ones(len(x))]).T
linfit=np.dot(np.linalg.inv(np.dot(a.T,a)),np.dot(a.T,y))
print(linfit)

lstsqr=np.linalg.lstsq(a,y)[0]
print(lstsqr)

m,n=np.polyfit(x,y,1)
xn=np.linspace(0,10,100)
yn=np.polyval([m,n],xn)
plt.plot(xn,yn)