Mercurial > hg > camir-aes2014
diff toolboxes/FullBNT-1.0.7/KPMtools/entropy.m @ 0:e9a9cd732c1e tip
first hg version after svn
author | wolffd |
---|---|
date | Tue, 10 Feb 2015 15:05:51 +0000 |
parents | |
children |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/toolboxes/FullBNT-1.0.7/KPMtools/entropy.m Tue Feb 10 15:05:51 2015 +0000 @@ -0,0 +1,17 @@ +function H = entropy(v, scale) +% ENTROPY Entropy log base 2 +% H = entropy(v) +% If v is a matrix, we compute the entropy of each column +% +% % H = entropy(v,1) means we scale the result so that it lies in [0,1] + +if nargin < 2, scale = 0; end + +v = v + (v==0); +H = -1 * sum(v .* log2(v), 1); % sum the rows + +if scale + n = size(v, 1); + unif = normalise(ones(n,1)); + H = H / entropy(unif); +end