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 Explanation
explain(BasicStats stats, double tf, double len)
Returns an explanation for the normalized term frequency.float
getZ()
Returns the parameterz
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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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)
whereA
measures 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: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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getZ
public float getZ()
Returns the parameterz
- See Also:
NormalizationZ(float)
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