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
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--- /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