Documentation
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Overview ¶
Package rerank holds the optional read-side rerank stage of recall: after hybrid retrieval and composite ranking, a reranker reads the query and the candidates together — something embeddings can't — and reorders them by how well each answers the query. Two implementations share the Reranker contract: a cross-encoder ranking model behind a /rerank endpoint (CrossEncoder) and a chat LLM prompted over a numbered list (NewLLM).
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Completer ¶ added in v0.0.6
Completer is the single-turn chat completion an LLM reranker needs. The chat clients in internal/llm satisfy it; declaring it here keeps this package free of a dependency on the chat backends.
type Config ¶
type Config struct {
// BaseURL is the API root (e.g. http://host:8002/v1); "/rerank" is appended.
BaseURL string
Model string
APIKey string
// MaxDocChars truncates each document before sending so an oversized
// candidate can't blow the server's physical batch and fail the whole
// request. 0 disables truncation.
MaxDocChars int
HTTPClient *http.Client
}
Config configures the cross-encoder reranker client.
type CrossEncoder ¶
type CrossEncoder struct {
// contains filtered or unexported fields
}
CrossEncoder reranks candidates with a dedicated ranking model (bge-reranker, Qwen3-Reranker, mxbai-rerank, …) served over the Cohere-style /rerank API that Infinity, vLLM, TEI, and llama-server --rerank expose — a cheaper alternative to the LLM reranker.
func New ¶
func New(cfg Config) (*CrossEncoder, error)
New builds a cross-encoder reranker client. BaseURL is required.
func (*CrossEncoder) Rerank ¶
func (c *CrossEncoder) Rerank(ctx context.Context, query string, candidates []Candidate) ([]string, error)
Rerank scores every candidate against the query with the ranking model and returns the candidate IDs most-relevant-first. Candidates the server omits are appended in their original order, satisfying the reorder-only contract of Reranker.
type Reranker ¶ added in v0.0.6
type Reranker interface {
// Rerank returns candidate IDs ordered most-relevant-first. Candidates the
// backend omits are appended in their original order, so reranking can only
// reorder, never drop, the input.
Rerank(ctx context.Context, query string, candidates []Candidate) ([]string, error)
}
Reranker reorders retrieved candidates by how well each answers a query.
Source Files