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Asked by huda nawaf on 5 Sep 2012

hi,

I try to built elbow code to determine the no. of clusters.I used the same data that used in the following link:

why I'm not get the same figure of elbow code in above link?

x = iris_dataset; x=x'; d=kmeans(x,9);

for i=1:10 a=find(d==i);

for j=1:length(a) cluster(i,j)=a(j); end end

for i=1:9 cluster1{i}=cluster(i,:); var1(i)=var(cluster1{i}); end s=sum(var1)/9; s1=var1/s; y(1:9)=1:9; plot(y,s1)

thanks in advance

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Answer by Doug Hull on 6 Sep 2012

Accepted answer

It looks to me like you are using the default settings for KMeans for the Start Parameter. This chooses a random starting subset. KMeans is NOT deterministic. You should expect different results each time, it is the nature of the algorithm.

huda nawaf on 9 Sep 2012

I do not think the reason in kmeans , but relate with somthing like scaling that thing I did not understand it.

thanks

Oleg Komarov on 9 Sep 2012

The reason IS in the randomized selection of the start position in kmeans.

Compare d between two runs of kmeans.

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