Entropy

from   numpy        import array
from   scipy.stats  import entropy
from   math         import log

base = 2


def e(*a):
    H = entropy(array(a), base=base)
    print(H)           

e( 1                           ) # 0.0                       | maximum value
e( 1/2     , 1/2               ) # 1.0                       | maximum value
e( 0.00001 , 0.99999           ) # 0.00018052328301819962    |
e( 1/3     , 1/3     , 1/3     ) # 1.584962500721156         | maximum value
e( 0.00001 , 0.00001 , 0.99998 ) # 0.00036104642176561263

#
# Maximum entropy for 1, 2 and 3 categories:
#
print(log(1, base)) # 0.0
print(log(2, base)) # 1.0
print(log(3, base)) # 1.5849625007211563