Class Similarity.SimScorer
- java.lang.Object
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- org.apache.lucene.search.similarities.Similarity.SimScorer
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- Enclosing class:
- Similarity
public abstract static class Similarity.SimScorer extends Object
Stores the weight for a query across the indexed collection. This abstract implementation is empty; descendants ofSimilarityshould subclassSimWeightand define the statistics they require in the subclass. Examples include idf, average field length, etc.
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Constructor Summary
Constructors Modifier Constructor Description protectedSimScorer()Sole constructor.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description Explanationexplain(Explanation freq, long norm)Explain the score for a single documentabstract floatscore(float freq, long norm)Score a single document.
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Method Detail
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score
public abstract float score(float freq, long norm)Score a single document.freqis the document-term sloppy frequency and must be finite and positive.normis the encoded normalization factor as computed bySimilarity.computeNorm(FieldInvertState)at index time, or1if norms are disabled.normis never0.Score must not decrease when
freqincreases, ie. iffreq1 > freq2, thenscore(freq1, norm) >= score(freq2, norm)for any value ofnormthat may be produced bySimilarity.computeNorm(FieldInvertState).Score must not increase when the unsigned
normincreases, ie. ifLong.compareUnsigned(norm1, norm2) > 0thenscore(freq, norm1) <= score(freq, norm2)for any legalfreq.As a consequence, the maximum score that this scorer can produce is bound by
score(Float.MAX_VALUE, 1).- Parameters:
freq- sloppy term frequency, must be finite and positivenorm- encoded normalization factor or1if norms are disabled- Returns:
- document's score
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explain
public Explanation explain(Explanation freq, long norm)
Explain the score for a single document- Parameters:
freq- Explanation of how the sloppy term frequency was computednorm- encoded normalization factor, as returned bySimilarity.computeNorm(org.apache.lucene.index.FieldInvertState), or1if norms are disabled- Returns:
- document's score
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