Class NormalizationZ
java.lang.Object
org.apache.lucene.search.similarities.Normalization
org.apache.lucene.search.similarities.NormalizationZ
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
Nested classes/interfaces inherited from class org.apache.lucene.search.similarities.Normalization
Normalization.NoNormalization
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Constructor Summary
ConstructorDescriptionCallsNormalizationZ(0.3)
NormalizationZ
(float z) Creates NormalizationZ with the supplied parameterz
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Method Summary
Modifier and TypeMethodDescriptionexplain
(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.toString()
Subclasses must override this method to return the code of the normalization formula.
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Constructor Details
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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 Details
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tfn
Description copied from class:Normalization
Returns the normalized term frequency.- Specified by:
tfn
in classNormalization
len
- the field length.
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explain
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
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:
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