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