> > Is it possible to use the clustering component to use predefined clusters > generated by Mahout?
Actually, the existing Solr ClusteringComponent's API has been designed to deal with both search results clustering (implemented by Carrot2) and off-line clustering of the whole index. The latter has not yet been implemented, so the API is very likely to change depending on the specific design decisions (should clustering be triggered through Solr or externally?, should the clusters be stored in Solr?, how to handle new documents?, how to use the clusters at search time?). I can also imagine a simpler approach based on a search results clustering "algorithm" that would simply fetch Mahout's predefined clusters for each document being returned in the search result. Getting this to work is a matter of implementing a dedicated http://lucene.apache.org/solr/api/org/apache/solr/handler/clustering/SearchClusteringEngine.html and should be fairly straightforward, at least in terms of interaction with Solr. Staszek
