Affinity Propagation preferences initialization

Question

I need to perform clustering without knowing in advance the number of clusters. The number of cluster may be from 1 to 5, since I may find cases where all the samples belong to

Answer 1

You can also merge clusters together by essentially running the algorithm a second time using the center samples or manually merging the most similar ones. So you could iteratively merge the closest clusters till you get your number, making the choice of preference easier since you can just choose anything that will result in a decent number of clusters (This worked decently well when I tried).