backend/reranker.py

from FlagEmbedding import FlagReranker

reranker = FlagReranker('BAAI/bge-reranker-large',
                        use_fp16=True)


def rerank(query: str, documents: [str], k: int) -> [str]:
    scores = reranker.compute_score([(query, document) for document in documents])
    sorted_docs = sorted(zip(scores, documents), key=lambda x: x[0], reverse=True)
    return [sorted_doc[1] for sorted_doc in sorted_docs[:k]]