Class Normalization
- java.lang.Object
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- org.apache.lucene.search.similarities.Normalization
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- Direct Known Subclasses:
Normalization.NoNormalization
,NormalizationH1
,NormalizationH2
,NormalizationH3
,NormalizationZ
public abstract class Normalization extends Object
This class acts as the base class for the implementations of the term frequency normalization methods in the DFR framework.- See Also:
DFRSimilarity
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
Normalization.NoNormalization
Implementation used when there is no normalization.
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Constructor Summary
Constructors Constructor Description Normalization()
Sole constructor.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description Explanation
explain(BasicStats stats, float tf, float len)
Returns an explanation for the normalized term frequency.abstract float
tfn(BasicStats stats, float tf, float len)
Returns the normalized term frequency.abstract String
toString()
Subclasses must override this method to return the code of the normalization formula.
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Method Detail
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tfn
public abstract float tfn(BasicStats stats, float tf, float len)
Returns the normalized term frequency.- Parameters:
len
- the field length.
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explain
public Explanation explain(BasicStats stats, float tf, float len)
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.
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