[R] classification algorithms with distance matrix

[sidahmed BENABDERRAHMANE]

Dear all,

I have a problem when using some classification functions (Kmeans, PAM, 
FANNY...)  with a distance matrix, and i would to understand how it 
proceeds for the positioning of centroids after one execution step.

In fact, in the classical formulation of the algorithm, after each step, 
to re-position the center, it calculates the distance between any 
elements of the old cluster and its center, or in my case I used  a 
distance matrix , so I do not understand how the algorithm can 
recalculates the distance between the newly generated center and other 
elements of the cluster knowing that the new center does not appear in 
the distance matrix and there is no way to calculate the distance 
between him and the elements of a cluster. ?

Thank you for your help.

Sid., LORIA
France.