class 
Axiomatic 
Axiomatic approaches for IR.

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) =
(docLenqueryLen)*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) =
(docLenqueryLen)*queryLen*s/avdl NOTE: the gamma function of this similarity creates negative
scores

class 
DFISimilarity 
Implements the Divergence from Independence (DFI) model based on Chisquare statistics
(i.e., standardized Chisquared distance from independence in term frequency tf).

class 
DFRSimilarity 
Implements the divergence from randomness (DFR) framework introduced in Gianni Amati and
Cornelis Joost Van Rijsbergen.

class 
IBSimilarity 
Provides a framework for the family of informationbased models, as described in Stéphane
Clinchant and Eric Gaussier.

class 
IndriDirichletSimilarity 
Bayesian smoothing using Dirichlet priors as implemented in the Indri Search engine
(http://www.lemurproject.org/indri.php).

class 
LMDirichletSimilarity 
Bayesian smoothing using Dirichlet priors.

class 
LMJelinekMercerSimilarity 
Language model based on the JelinekMercer smoothing method.

class 
LMSimilarity 
Abstract superclass for language modeling Similarities.
