Class AxiomaticF1EXP
- java.lang.Object
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- org.apache.lucene.search.similarities.Similarity
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- org.apache.lucene.search.similarities.SimilarityBase
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- org.apache.lucene.search.similarities.Axiomatic
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- org.apache.lucene.search.similarities.AxiomaticF1EXP
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public class AxiomaticF1EXP extends Axiomatic
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- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.search.similarities.Similarity
Similarity.SimScorer, Similarity.SimWeight
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Field Summary
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Fields inherited from class org.apache.lucene.search.similarities.SimilarityBase
discountOverlaps
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Constructor Summary
Constructors Constructor Description AxiomaticF1EXP()
Default constructorAxiomaticF1EXP(float s)
Constructor setting s only, letting k and queryLen to defaultAxiomaticF1EXP(float s, float k)
Constructor setting s and k, letting queryLen to default
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected float
gamma(BasicStats stats, float freq, float docLen)
compute the gamma componentprotected float
idf(BasicStats stats, float freq, float docLen)
compute the inverted document frequency componentprotected float
ln(BasicStats stats, float freq, float docLen)
compute the document length componentprotected float
tf(BasicStats stats, float freq, float docLen)
compute the term frequency componentprotected float
tfln(BasicStats stats, float freq, float docLen)
compute the mixed term frequency and document length componentString
toString()
Name of the axiomatic method.-
Methods inherited from class org.apache.lucene.search.similarities.SimilarityBase
computeNorm, computeWeight, explain, fillBasicStats, getDiscountOverlaps, log2, newStats, setDiscountOverlaps, simScorer
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Constructor Detail
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AxiomaticF1EXP
public AxiomaticF1EXP(float s, float k)
Constructor setting s and k, letting queryLen to default- Parameters:
s
- hyperparam for the growth functionk
- hyperparam for the primitive weighting function
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AxiomaticF1EXP
public AxiomaticF1EXP(float s)
Constructor setting s only, letting k and queryLen to default- Parameters:
s
- hyperparam for the growth function
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AxiomaticF1EXP
public AxiomaticF1EXP()
Default constructor
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Method Detail
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toString
public String toString()
Description copied from class:Axiomatic
Name of the axiomatic method.
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tf
protected float tf(BasicStats stats, float freq, float docLen)
compute the term frequency component
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ln
protected float ln(BasicStats stats, float freq, float docLen)
compute the document length component
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tfln
protected float tfln(BasicStats stats, float freq, float docLen)
compute the mixed term frequency and document length component
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idf
protected float idf(BasicStats stats, float freq, float docLen)
compute the inverted document frequency component
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gamma
protected float gamma(BasicStats stats, float freq, float docLen)
compute the gamma component
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