[FIXED] logarithmic calculation issue in python jupyter notebook

Issue

In jupyter notebook i tried to execute below code:

from math import log2
-((25/50)*log2(25/50))+((25/50)*log2(25/50))

output which am receiving is 0.0

it should be 1, what is the issue???

Solution

this is actually a math issue. not programming. the last thing must come in mind is that python is working wrong!
both sides of + are equal and one of them has multiplied by -1. so it is like you are calculating this: -x+x and it is equal to 0.
I guess you have this in mind: -((25/50) * log2(25/50) + (25/50) * log2(25/50)). In this case, you will have an equation like:-(x+x). so you will get 1 for the answer.

>>> from math import log2
>>> -((25/50) * log2(25/50)) + ((25/50) * log2(25/50))
# 0.0
>>> -((25/50) * log2(25/50) + (25/50) * log2(25/50))
# 1.0

Answered By - FarZad