Mahout PreferenceArray userID uniqeness?

Question

Does the userId of a preferenceArray need to be unique across all entries in a FastByIDMap?

I'm comparing two types of objects that contain similar traits however it's possible that their id (primary key) is not unique as it's two db tables.

Thanks.

Answer 1

Via the Mahout user mailing list, userID's in a FastByIDMap must be unique over the entire map.