FPSR+: Toward Robust, Efficient and Scalable Collaborative Filtering With Partition-aware Item Similarity Modeling

Collaborative filtering (CF) has been extensively studied in recommendation, spawning various solutions. While graph convolution networks (GCNs) are effective at representation learning, their efficiency is lacking. Comparatively, item similarity model efficiently establishes direct relationships between items. In spite of this, the modeling problem grows quadratically as the number of items increases. This poses critical scalability issues. In this paper, through an investigation of the latest GCN model, we reveal the feasibility of optimizing the process of similarity modeling using the underlying group structure in the item set. Based on these findings, we propose a novel model which introduces graph partitioning to reduce the scale of similarity modeling problem, dubbed FPSR+. Specifically, we divide similarity modeling of items into sub-problems within each partition, and incorporate global and local prior knowledge to alleviate information loss. Following an analysis of the properties of different items in partitioning, we propose a new hub set selection strategy that improves the robustness of FPSR+ in the small partition case. Extensive experiments on four real-world datasets demonstrate the superior performance of FPSR+ compared with state-of-the-art GCN models and item similarity models, as well as several-fold speedups and reductions in parameter storage.