mmr-rerank
Maximal Marginal Relevance (Carbonell & Goldstein 1998) reranker. Balances query relevance against pairwise novelty so retrieved chunks don't all say the same thing.
use mmr;
let rel = vec!;
let pair = vec!;
let picks = mmr;
// [0, 2] — top relevance, then diverse from it
Zero deps. MIT or Apache-2.0.