# Uses of Class
org.apache.lucene.search.similarities.Axiomatic

Packages that use Axiomatic
Package
Description
org.apache.lucene.search.similarities
This package contains the various ranking models that can be used in Lucene.

- ## Uses of Axiomatic in org.apache.lucene.search.similarities

  Subclasses of Axiomatic in org.apache.lucene.search.similarities
  Modifier and Type
  Class
  Description
  `class`
  `AxiomaticF1EXP`
  F1EXP is defined as Sum(tf(term_doc_freq)*ln(docLen)*IDF(term)) where IDF(t) = pow((N+1)/df(t), k) N=total num of docs, df=doc freq
  `class`
  `AxiomaticF1LOG`
  F1LOG is defined as Sum(tf(term_doc_freq)*ln(docLen)*IDF(term)) where IDF(t) = ln((N+1)/df(t)) N=total num of docs, df=doc freq
  `class`
  `AxiomaticF2EXP`
  F2EXP is defined as Sum(tfln(term_doc_freq, docLen)*IDF(term)) where IDF(t) = pow((N+1)/df(t), k) N=total num of docs, df=doc freq
  `class`
  `AxiomaticF2LOG`
  F2EXP is defined as Sum(tfln(term_doc_freq, docLen)*IDF(term)) where IDF(t) = ln((N+1)/df(t)) N=total num of docs, df=doc freq
  `class`
  `AxiomaticF3EXP`
  F3EXP is defined as Sum(tf(term_doc_freq)*IDF(term)-gamma(docLen, queryLen)) where IDF(t) = pow((N+1)/df(t), k) N=total num of docs, df=doc freq gamma(docLen, queryLen) = (docLen-queryLen)*queryLen*s/avdl NOTE: the gamma function of this similarity creates negative scores
  `class`
  `AxiomaticF3LOG`
  F3EXP is defined as Sum(tf(term_doc_freq)*IDF(term)-gamma(docLen, queryLen)) where IDF(t) = ln((N+1)/df(t)) N=total num of docs, df=doc freq gamma(docLen, queryLen) = (docLen-queryLen)*queryLen*s/avdl NOTE: the gamma function of this similarity creates negative scores