Class Normalization
java.lang.Object
org.apache.lucene.search.similarities.Normalization
- Direct Known Subclasses:
Normalization.NoNormalization
,NormalizationH1
,NormalizationH2
,NormalizationH3
,NormalizationZ
This class acts as the base class for the implementations of the term
frequency normalization methods in the DFR framework.
- See Also:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic final class
Implementation used when there is no normalization. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionexplain
(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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Constructor Details
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Normalization
public Normalization()Sole constructor. (For invocation by subclass constructors, typically implicit.)
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Method Details
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tfn
Returns the normalized term frequency.- Parameters:
len
- the field length.
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explain
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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toString
Subclasses must override this method to return the code of the normalization formula. Refer to the original paper for the list.
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