Python3 np.cov giving strange result

Question

import numpy as np    

X = np.arange(6).reshape(2,3)
np.cov(X)

#Results in:
array([[1., 1.],
       [1., 1.]])

While it should output:

array([[0.66666667, 0.66666667],
       [0.66666667, 0.66666667]])

Answer 1

As mentioned in comments, the default cov is normalized by N-1 which is an unbiased estimate. To get simple average you can do either of these solutions:

np.cov(X,bias=True)

or

np.cov(X,ddof=0)

output:

[[0.66666667 0.66666667]
 [0.66666667 0.66666667]]