In [ ]:

    

import math


    

In [ ]:

    

math.log(1)


    

In [ ]:

    

-math.log(1)


    

In [ ]:

    

-math.log(0.00001)


    

In [ ]:

    

a = np.random.randn(3, 3)
b = np.random.randn(3, 1)
c = a*b


    

In [ ]:

    

a = np.random.randn(4, 3) # a.shape = (4, 3)
b = np.random.randn(3, 2) # b.shape = (3, 2)
c = a*b


    

In [ ]:

    

A = np.array([[1,0],[0,1], [0,0]])


    

In [ ]:

    

A_normed = A/np.linalg.norm(A, axis=0)


    

In [ ]:

    

np.matmul(A_normed,A_normed.T)


    

In [ ]:

    

np.matmul(A.T,A)


    

In [ ]: