Okapi BM25

This is a popular algorithm in Information retrieval, especially useful for Full-text search. It is similar to TF-IDF.

I’ve heard BM25 stands for Best Match 25.

Useful links

https://en.wikipedia.org/wiki/Okapi_BM25
https://nlp.stanford.edu/IR-book/html/htmledition/okapi-bm25-a-non-binary-model-1.html