均值变点

 1 function pos = meanChangePoint(X)
 2 %     X = [0 X];
 3     len = length(X);
 4     if(len<2)
 5         pos = -1;
 6         return;
 7     end
 8     meanT = mean(X);
 9     meanT = repmat(meanT,1,size(X,2));
10     stdT = sum((X - meanT).^2);
11     resS = [];
12     for i = 2:len
13         mean1  = mean(X(1:i-1));
14         vecmean1 = repmat(mean1,1,i-1);    
15         mean2 = mean(X(i:len));
16         vecmean2 = repmat(mean2,1,len - i +1);            
17         stdI = sum((X(1:i-1) - vecmean1).^2) + sum((X(i:len) - vecmean2).^2);
18         tmp = stdT - stdI;
19         resS = [resS tmp];
20     end
21     [~,pos] = max(resS);
22 end