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Glossary: System Design Beyond the Basics in C++

BM25

Also written: Okapi BM25

The standard search relevance formula. Rare words count more than common ones, and long texts count a little less, so 'chocolatey' outranks 'espresso' in Kettle & Crane's products.

Where the book teaches it

Related terms

Inverted indexRankingIDF (inverse document frequency)Term frequency