RE: log2 calculations, entropy

[Stumpo, Cody (C.M.)]

log a (x) = log b (x) / log b (a)

So you can manually do the conversion that way.  I always understood entropy
to be base 2 so you could express it in terms of bits, but I guess it's not
strictly necessary. 

Cody

--
Mathematics is the part of science you could continue to do if you woke up
tomorrow and discovered the universe was gone.

> -----Original Message-----
> From: Paul Johnson [SMTP:address@hidden
> Sent: Monday, August 09, 1999 3:49 PM
> To:   address@hidden
> Subject:      log2 calculations, entropy
> 
> I can't figure how to get a logarithm to the base 2. Can someone help? 
> I have included math.h.  log10 and log work. but log2 doesn't.
> 
> I want that to calculate entropy.  The article "Social Entropy: An
> Information Theoretic Measure of Robot Team Diversity," by Tucker Balch,
> which was announced in this list, says you need to use log2, not natural
> log in calculating entropy.
> 
> While looking for an answer, I notice in the swarm
> src/analysis/Entropy.m, that the natual log is used to calculate
> entropy, not log base 2.  If Balch is correct, the current method is
> wrong.
> 
> 
> -- 
> Paul E. Johnson                       email: address@hidden
> Dept. of Political Science            http://lark.cc.ukans.edu/~pauljohn
> University of Kansas                  Office: (785) 864-9086
> Lawrence, Kansas 66045                FAX: (785) 864-5700
> 
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