[Eeglablist] Silhouette value for IC clustering

[Bernhardsson Jens]

Hi,

I believe that the Silhouette value found in A10: MI-clust is based on kmeans cluster of multidimensional scaled data performed on the mutual information matrix and the kmeans found in STUDY is based on a pca derived (pre clustering) array. You can run the code below after you pre cluster in STUDY to get the mean and individual Silhouette coefficients for different cluster solutions.

avgSil = []; 
kmod = []; 
siSil = []; 
 
for num_of_cluster = 2:25
    kmod = kmeans(STUDY.etc.preclust.preclustdata,num_of_cluster, 'replicates',10,'emptyaction','drop','distance','sqEuclidean');  
    siSil(:,num_of_cluster-1) = silhouette(STUDY.etc.preclust.preclustdata,kmod,'sqEuclidean');
    avgSil = [avgSil; num_of_cluster mean(siSil(:,num_of_cluster-1))];
end
 
figure;  
plot( avgSil(:,1),avgSil(:,2),'r*-.');
% ylim([0 1])
set(gca,'XTick',1:num_of_cluster, 'XGrid', 'on');


Regards,
Jens

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Skickat: den 17 september 2017 15:43
Till: eeglablist at sccn.ucsd.edu
Ämne: [Eeglablist] Silhouette value for IC clustering

Dear EEGLAB users,

I understand that the determination of the number of clusters in IC clustering is one of the difficult problems in source localizations by ICs. Silhouette value is one of the criteria for the best number of clusters in IC clustering, and I have found the description of silhouette value in EEGLAB Wiki (A10: MI-clust) for a single participant. Can we get silhouette values for group data in STUDY formats? Thank you in advance.

******************************************
Shingo Tokimoto, Ph.D.
in Linguistics and Psychology
Department of Foreign Languages
Mejiro University
4-31-1, Naka-Ochiai, Shinjuku, Tokyo,
161-8539, Japan
tokimoto at mejiro.ac.jp
******************************************

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