%利用Adjusted?Cosine法計(jì)算電影a和b的相似度
%這個(gè)算法雖然可以求出相似度矩陣，但是有個(gè)問題就是，當(dāng)共同評(píng)價(jià)電影a和b的用戶
%只有一個(gè)的時(shí)候，結(jié)果只有兩種可能，即1或者是-1。這就需要在找鄰居時(shí)要避免選擇
%這些情況的相似度電影。
function?Sim_ab=Similarity_ab（score_matrixab）
%找出所有評(píng)價(jià)所電影a和b的用戶集合（標(biāo)號(hào)）
temp=score_matrix（:a）&score_matrix（:b）;
P_ab=find（temp）;
P_ab=P_ab‘;%用行向量存儲(chǔ)所有評(píng)價(jià)電影a和b的用戶
%end
%%?利用Adjusted?Cosine法計(jì)算相似度
if?isempty（P_ab）
????Sim_ab=0;
else
????[~temp]=size（P_ab）;%共同評(píng)價(jià)電影a和b的用戶的數(shù)目
????%[~number_movies]=size（score_matrix）;
????sum1=0;
????sum2=0;
????sum3=0;
????for?i=1:temp?%注意此處的temp已經(jīng)不是數(shù)組了
????????[~m]=size（find（score_matrix（P_ab（i）:）~=0））;%計(jì)算該用戶評(píng)價(jià)的電影個(gè)數(shù)
????????sum_score=sum（score_matrix（P_ab（i）:）2）;%用戶對(duì)所有電影的總評(píng)分
????????aver_score=sum_score/m;
????????sum1=sum1+（score_matrix（P_ab（i）a）-aver_score）*（score_matrix（P_ab（i）b）-aver_score）;
????????sum2=sum2+（score_matrix（P_ab（i）a）-aver_score）^2;
????????sum3=sum3+（score_matrix（P_ab（i）b）-aver_score）^2;
????end
????if?sum2==0||sum3==0
????????Sim_ab=0;
????else
????????Sim_ab=sum1/sqrt（sum2*sum3）;
????end
end

?屬性????????????大小?????日期????時(shí)間???名稱
-----------?---------??----------?-----??----

?????文件????????716??2015-09-18?11:19??ItembaseCF__u1\ml-100k\allbut.pl

?????文件????????643??2015-09-18?11:19??ItembaseCF__u1\ml-100k\mku.sh

?????文件???????6403??2015-09-18?11:19??ItembaseCF__u1\ml-100k\README

?????文件????1979173??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u.data

?????文件????????202??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u.genre

?????文件?????????36??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u.info

?????文件?????236344??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u.item

?????文件????????193??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u.occupation

?????文件??????22628??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u.user

?????文件????1586544??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u1.base

?????文件?????392629??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u1.test

?????文件????1583948??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u2.base

?????文件?????395225??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u2.test

?????文件????1582546??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u3.base

?????文件?????396627??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u3.test

?????文件????1581878??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u4.base

?????文件?????397295??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u4.test

?????文件????1581776??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u5.base

?????文件?????397397??2015-09-18?11:19??ItembaseCF__u1\ml-100k\u5.test

?????文件????1792501??2015-09-18?11:19??ItembaseCF__u1\ml-100k\ua.base

?????文件?????186672??2015-09-18?11:19??ItembaseCF__u1\ml-100k\ua.test

?????文件????1792476??2015-09-18?11:19??ItembaseCF__u1\ml-100k\ub.base

?????文件?????186697??2015-09-18?11:19??ItembaseCF__u1\ml-100k\ub.test

?????文件???????1202??2015-04-25?20:24??ItembaseCF__u1\Similarity_ab.m

?????文件????9392887??2015-10-29?22:41??ItembaseCF__u1\SimilitudItems.mat

?????文件???????3168??2015-10-29?22:53??ItembaseCF__u1\testRead.m

?????文件????1586544??2001-03-09?02:33??ItembaseCF__u1\u1.base

?????文件?????392629??2001-03-09?02:32??ItembaseCF__u1\u11.test

?????目錄??????????0??2016-03-14?21:55??ItembaseCF__u1\ml-100k

?????目錄??????????0??2016-03-14?21:55??ItembaseCF__u1

............此處省略3個(gè)文件信息