Luo Si and Rong Jin
This paper presents a flexible mixture model (FMM) for collaborative filtering. FMM extends existing partitioning/clustering algorithms for collaborative filtering by clustering both users and items together simultaneously without assuming that each user and item should only belong to a single cluster. Furthermore, with the introduction of "preference" nodes, the proposed framework is able to explicitly model how users rate items, which can vary dramatically, even among the users with similar tastes on items. Empirical study over two datasets of movie ratings has shown that our new algorithm outperforms five other collaborative filtering algorithms substantially.