www.gusucode.com > K聚类分析源码程序 > K聚类分析源码程序/code/infoentropy.m
function H = infoentropy(L) %INFOENTROPY Entropy of information. % H = INFOENTROPY(L) returns the entropy of information for an N-by-1 % integer array of classification data, L. % % Copyright (2009) Sandia Corporation. Under the terms of Contract % DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains % certain rights in this software. N = length(L); k = unique(L); H = 0; % loop over the unique elements of L for i = 1:size(k,1) % the probability of a given classification index occurring in L pk = sum(k(i) == L)/N; H = H - pk*log(pk); end