Hi, I'm trying to evaluate my recommender system in Mahout. I have boolean data and I'm using *GenericBooleanPrefUserBasedRecommender* I used precision and recall and it's returning *throwing java.lang.IllegalArgumentException: Illegal nDCG: NaN** * * * Does this mean I don't have enough data to evaluate? Is there any way to do evaluation on this data?
Thank you * Agata Filiana **http://about.me/dewtraveller* <http://about.me/dewtraveller>* *
