function?MIhat?=?nmi（?A?B?）?
????%NMI?Normalized?mutual?information
????%?http://en.wikipedia.org/wiki/Mutual_information
????%?http://nlp.stanford.edu/IR-book/html/htmledition/evaluation-of-clustering-1.html

????%?Author:?http://www.cnblogs.com/ziqiao/???[2011/12/13]?

????if?length（?A?）?~=?length（?B）
????????error（‘length（?A?）?must?==?length（?B）‘）;
????end
????total?=?length（A）;
????A_ids?=?unique（A）;
????B_ids?=?unique（B）;

????%?Mutual?information
????MI?=?0;
????for?idA?=?A_ids
????????for?idB?=?B_ids
?????????????idAOccur?=?find（?A?==?idA?）;
?????????????idBOccur?=?find（?B?==?idB?）;
?????????????idABOccur?=?intersect（idAOccuridBOccur）;?

?????????????px?=?length（idAOccur）/total;
?????????????py?=?length（idBOccur）/total;
?????????????pxy?=?length（idABOccur）/total;

?????????????MI?=?MI?+?pxy*log2（pxy/（px*py）+eps）;?%?eps?:?the?smallest?positive?number

????????end
????end

????%?Normalized?Mutual?information
????Hx?=?0;?%?Entropies
????for?idA?=?A_ids
????????idAOccurCount?=?length（?find（?A?==?idA?）?）;
????????Hx?=?Hx?-?（idAOccurCount/total）?*?log2（idAOccurCount/total?+?eps）;
????end
????Hy?=?0;?%?Entropies
????for?idB?=?B_ids
????????idBOccurCount?=?length（?find（?B?==?idB?）?）;
????????Hy?=?Hy?-?（idBOccurCount/total）?*?log2（idBOccurCount/total?+?eps）;
????end

????MIhat?=?2?*?MI?/?（Hx+Hy）;
end

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2015-05-31?10:57??nmi\
?????文件??????263222??2009-12-18?02:54??nmi\22.bmp
?????文件??????263222??2009-12-18?02:54??nmi\23.bmp
?????文件??????263222??2009-12-18?02:54??nmi\24.bmp
?????文件??????263222??2009-12-18?02:58??nmi\25.bmp
?????文件??????263222??2009-12-18?02:57??nmi\26.bmp
?????文件??????263222??2009-12-18?02:57??nmi\27.bmp
?????文件????????1365??2015-05-26?20:27??nmi\nmi.m
?????文件????????1129??2015-05-26?20:33??nmi\nmimem.m