Shannon Entropy coding
Question:
I am trying to write a Shannon entropy code and test it. Although testing with "aaaaa" should give me 0.0. it gives me -0.0 is there anyway to fix that?
[CODE]
Answers:
Since -0.0 == 0.0 is true, what you have is mathematically correct. If you find the output unaesthetic, the fix is simple. Don’t multiply by -1. Take the absolute value instead:
from collections import Counter
import math
def entropy(string):
counts = Counter(string)
rel_freq = ((i/len(string)) for i in counts.values())
return abs(sum(f*math.log2(f) for f in rel_freq))
Then entropy('aaaaa') evaluates to 0.0.
I am trying to write a Shannon entropy code and test it. Although testing with "aaaaa" should give me 0.0. it gives me -0.0 is there anyway to fix that?
[CODE]
Since -0.0 == 0.0 is true, what you have is mathematically correct. If you find the output unaesthetic, the fix is simple. Don’t multiply by -1. Take the absolute value instead:
from collections import Counter
import math
def entropy(string):
counts = Counter(string)
rel_freq = ((i/len(string)) for i in counts.values())
return abs(sum(f*math.log2(f) for f in rel_freq))
Then entropy('aaaaa') evaluates to 0.0.