Class NormalizationH2
- java.lang.Object
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- org.apache.lucene.search.similarities.Normalization
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- org.apache.lucene.search.similarities.NormalizationH2
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public class NormalizationH2 extends Normalization
Normalization model in which the term frequency is inversely related to the length.While this model is parameterless in the original article, the thesis introduces the parameterized variant. The default value for the
c
parameter is1
.- 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.Normalization
Normalization.NoNormalization
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Constructor Summary
Constructors Constructor Description NormalizationH2()
CallsNormalizationH2(1)
NormalizationH2(float c)
Creates NormalizationH2 with the supplied parameterc
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Explanation
explain(BasicStats stats, double tf, double len)
Returns an explanation for the normalized term frequency.float
getC()
Returns thec
parameter.double
tfn(BasicStats stats, double tf, double len)
Returns the normalized term frequency.String
toString()
Subclasses must override this method to return the code of the normalization formula.
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Constructor Detail
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NormalizationH2
public NormalizationH2(float c)
Creates NormalizationH2 with the supplied parameterc
.- Parameters:
c
- hyper-parameter that controls the term frequency normalization with respect to the document length.
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NormalizationH2
public NormalizationH2()
CallsNormalizationH2(1)
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Method Detail
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tfn
public final double tfn(BasicStats stats, double tf, double len)
Description copied from class:Normalization
Returns the normalized term frequency.- Specified by:
tfn
in classNormalization
len
- the field length.
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explain
public Explanation explain(BasicStats stats, double tf, double len)
Description copied from class:Normalization
Returns an explanation for the normalized term frequency.The default normalization methods use the field length of the document and the average field length to compute the normalized term frequency. This method provides a generic explanation for such methods. Subclasses that use other statistics must override this method.
- Overrides:
explain
in classNormalization
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toString
public String toString()
Description copied from class:Normalization
Subclasses must override this method to return the code of the normalization formula. Refer to the original paper for the list.- Specified by:
toString
in classNormalization
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getC
public float getC()
Returns thec
parameter.- See Also:
NormalizationH2(float)
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