PGT: Pseudo Relevance Feedback Using a Graph-Based Transformer
HongChien Yu Computer Science Department School of Computer Science Carnegie Mellon University hongqiay@cs.cmu.edu |
Zhuyun Dai Language Technologies Institute School of Computer Science Carnegie Mellon University zhuyund@cs.cmu.edu |
Jamie Callan Language Technologies Institute School of Computer Science Carnegie Mellon University callan@cs.cmu.edu |
Most research on pseudo relevance feedback (PRF) has been done in vector space and probabilistic retrieval models. This paper shows that Transformer-based rerankers can also benefit from the extra context that PRF provides. It presents PGT, a graph-based Transformer that sparsifies attention between graph nodes to enable PRF while avoiding the high computational complexity of most Transformer architectures. Experiments show that PGT improves upon non-PRF Transformer reranker, and it is at least as accurate as Transformer PRF models that use full attention, but with lower computational costs.
Source code are in the GihHub repositorty. It covers: