Comparison
Bi-encodervsCross-encoder
Bi-encoder
A bi-encoder embeds query and document separately, enabling precomputed indexes.
Cross-encoder
A cross-encoder reads them together and scores the pair, more accurate but unindexable.
The difference
A bi-encoder embeds query and document separately, enabling precomputed indexes; a cross-encoder reads them together and scores the pair, more accurate but unindexable. Retrieval uses bi-encoders, reranking uses cross-encoders. That sentence explains the whole retrieval-then-rerank architecture.
Entry: Bi-encoder vs cross-encoder →