reranker.py

from sklearn.metrics.pairwise import cosine_similarity


from text_embedder_encoder import TextEmbedder


class Reranker:
    def __init__(self):
        self.text_embedder = TextEmbedder()

    def rerank(self, query, retrieved_docs, top_n=5):
        # Encode query and documents
        query_embedding = self.text_embedder.encode(query)
        doc_embeddings = self.text_embedder.encode_many(retrieved_docs)
        similarity_scores = cosine_similarity([query_embedding], doc_embeddings)[0]

        similarity_scores_with_idxes = list(zip(similarity_scores, range(len(similarity_scores))))
        similarity_scores_with_idxes.sort(reverse=True)
        similarity_scores_with_idxes_final = similarity_scores_with_idxes[:top_n]
        reranked_docs = [retrieved_docs[idx] for score, idx in similarity_scores_with_idxes_final if score >= 0.7]

        return reranked_docs