Class Similarity.SimScorer
java.lang.Object
org.apache.lucene.search.similarities.Similarity.SimScorer
- Enclosing class:
Similarity
Stores the weight for a query across the indexed collection. This abstract implementation is
empty; descendants of
Similarity should subclass SimWeight and define the
statistics they require in the subclass. Examples include idf, average field length, etc.-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionexplain(Explanation freq, long norm) Explain the score for a single documentabstract floatscore(float freq, long norm) Score a single document.
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Constructor Details
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SimScorer
protected SimScorer()Sole constructor. (For invocation by subclass constructors.)
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Method Details
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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
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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