Class NormalizationZ
- java.lang.Object
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- org.apache.lucene.search.similarities.Normalization
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- org.apache.lucene.search.similarities.NormalizationZ
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public class NormalizationZ extends Normalization
Pareto-Zipf Normalization- 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 NormalizationZ()CallsNormalizationZ(0.3)NormalizationZ(float z)Creates NormalizationZ with the supplied parameterz.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Explanationexplain(BasicStats stats, double tf, double len)Returns an explanation for the normalized term frequency.floatgetZ()Returns the parameterzdoubletfn(BasicStats stats, double tf, double len)Returns the normalized term frequency.StringtoString()Subclasses must override this method to return the code of the normalization formula.
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Constructor Detail
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NormalizationZ
public NormalizationZ()
CallsNormalizationZ(0.3)
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NormalizationZ
public NormalizationZ(float z)
Creates NormalizationZ with the supplied parameterz.- Parameters:
z- representsA/(A+1)whereAmeasures the specificity of the language. It ranges from (0 .. 0.5)
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Method Detail
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tfn
public double tfn(BasicStats stats, double tf, double len)
Description copied from class:NormalizationReturns the normalized term frequency.- Specified by:
tfnin classNormalizationlen- the field length.
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explain
public Explanation explain(BasicStats stats, double tf, double len)
Description copied from class:NormalizationReturns 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:
explainin classNormalization
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toString
public String toString()
Description copied from class:NormalizationSubclasses must override this method to return the code of the normalization formula. Refer to the original paper for the list.- Specified by:
toStringin classNormalization
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getZ
public float getZ()
Returns the parameterz- See Also:
NormalizationZ(float)
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