comparison 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
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-1:000000000000 0:e9a9cd732c1e
1 function H = entropy(v, scale)
2 % ENTROPY Entropy log base 2
3 % H = entropy(v)
4 % If v is a matrix, we compute the entropy of each column
5 %
6 % % H = entropy(v,1) means we scale the result so that it lies in [0,1]
7
8 if nargin < 2, scale = 0; end
9
10 v = v + (v==0);
11 H = -1 * sum(v .* log2(v), 1); % sum the rows
12
13 if scale
14 n = size(v, 1);
15 unif = normalise(ones(n,1));
16 H = H / entropy(unif);
17 end