IBM25Similarity
BM25 Similarity. Introduced in Stephen E. Robertson, Steve Walker, Susan Jones, Micheline Hancock-Beaulieu,
and Mike Gatford. Okapi at TREC-3. In Proceedings of the Third Text Retrieval Conference (TREC 1994). Gaithersburg, USA, November 1994.
Controls to what degree document length normalizes tf values.
Sets whether overlap tokens (Tokens with 0 position increment) are ignored when computing norm.
Controls non-linear term frequency normalization (saturation).