I have the following problem - made abstract to bring out the key issues.
I have 10 points each which is some distance from the other. I want to
This is not euclidean space. But the distances can be summarised as follows - p(i) is point i:
p(1) p(2) p(3) p(4) p(5) p(6) p(7) p(8) p(9) p(10)
p(1) 0 2 1 3 2 3 3 2 3 4
p(2) 2 0 1 3 2 3 3 2 3 4
p(3) 1 1 0 2 0 1 2 1 2 3
p(4) 3 3 2 0 1 2 3 2 3 4
p(5) 2 2 1 1 0 1 2 1 2 3
p(6) 3 3 2 2 1 0 3 2 3 4
p(7) 3 3 2 3 2 3 0 1 2 3
p(8) 2 2 1 2 1 2 1 0 1 2
p(9) 3 3 2 3 2 3 2 1 0 1
p(10) 4 4 3 4 3 4 3 2 1 0
How would I calculate which is the center point of this cluster?
As far as I understand this looks like K Means Clustering, and what you are looking for is usually known as 'Medoids'.
See here: http://en.wikipedia.org/wiki/Medoids or here: http://en.wikipedia.org/wiki/K-medoids