Dense Passage Retriever - is a set of tools and models for open-domain Q&A task. It is based on this research work and provides state-of-the-art results for multiple Q&A datasets. Features Dense retriever model is based on bi-encoder architecture. Extractive Q&A reader&ranker joint model inspired by this paper. Related data pre- and post- processing tools. Dense retriever component for inference time logic is based on FAISS index. github地址： https://github.com/facebookresearch/DPR