How do I find cluster center of each cluster gained from Spectral Clustering?

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Hi, I am using Spectral Clustering for data analysis recently and I found that Spectral Clustering function built in MATLAB only returns the cluster indicator (that is, "idx"). However, I actually need the cluster center of each cluster (similar to the centroid locations gained by k-means). How can I get it? Any idea or code would be very helpful.
Regards, Ning
  2 Comments
Riley
Riley on 29 Mar 2021
clear
clc
load('xi.mat');
K=100;
[idx]=spectralcluster(xi, K);
Thank you for reminding. This is code and data xi. 'idx' contains cluster indices of each sampling in xi.

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Accepted Answer

KSSV
KSSV on 29 Mar 2021
As you have indices in hand, you can get the centers....
clear
clc
load('xi.mat');
K=100;
[idx]=spectralcluster(xi, K);
C = zeros(k,2) ;
for i = 1:k
c = xi(idx==i) ; % this will give cluster
C(i,:) = mean(c) ; % calculate the mean
end
  2 Comments
Riley
Riley on 29 Mar 2021
Thanks for your code and idea. It's not what I exactly want but inspiring me!
Megh
Megh on 2 Aug 2022
I dont think it makes sense to take the mean since the mean is specifially optimized to minimize the euclidean distance from all the points in the given cluster to the cluster center, which turns out to be the mean after differentiating the MSE loss function and setting it to zero, as in k-means.

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