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Julie Tibshirani commented on LUCENE-9725: ------------------------------------------ That makes sense, I'll give it thought and we can discuss on LUCENE-8711 ! > Allow BM25FQuery to use other similarities > ------------------------------------------ > > Key: LUCENE-9725 > URL: https://issues.apache.org/jira/browse/LUCENE-9725 > Project: Lucene - Core > Issue Type: Improvement > Reporter: Julie Tibshirani > Priority: Major > Time Spent: 40m > Remaining Estimate: 0h > > From a high level, BM25FQuery works as follows: > # Given a list of fields and weights, it pretends there's a synthetic > combined field where all terms have been indexed. It computes new term and > collection statistics for this combined field. > # It uses a disjunction iterator and BM25Similarity to score the documents. > The steps are (1) compute statistics that represent the combined field > content, and (2) pass these to a similarity function. There is nothing really > specific to BM25Similarity in this approach. In step 2, we could use another > similarity, for example BooleanSimilarity or those based on language models > like LMDirichletSimilarity. The main restriction is that norms have to be > additive (the norm of the combined field must be the sum of the field norms). > Maybe we could unhardcode BM25Similarity in BM25FQuery and instead use the > one configured on IndexSearcher. We could think of this as providing a > sensible default approach to cross-field scoring for many similarities. It's > an incremental step towards LUCENE-8711, which would give similarities more > fine-grained control over how stats/ scores are combined across fields. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org