Class LegacyBM25Similarity
- java.lang.Object
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- org.apache.lucene.search.similarities.Similarity
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- org.apache.lucene.search.similarity.LegacyBM25Similarity
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@Deprecated public final class LegacyBM25Similarity extends Similarity
Deprecated.BM25Similarity
should be used insteadSimilarity that behaves likeBM25Similarity
while also applying the k1+1 factor to the numerator of the scoring formula- See Also:
BM25Similarity
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.search.similarities.Similarity
Similarity.SimScorer
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Constructor Summary
Constructors Constructor Description LegacyBM25Similarity()
Deprecated.BM25 with these default values:k1 = 1.2
b = 0.75
LegacyBM25Similarity(float k1, float b)
Deprecated.BM25 with the supplied parameter values.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description long
computeNorm(FieldInvertState state)
Deprecated.float
getB()
Deprecated.Returns theb
parameterboolean
getDiscountOverlaps()
Deprecated.Returns true if overlap tokens are discounted from the document's length.float
getK1()
Deprecated.Returns thek1
parameterSimilarity.SimScorer
scorer(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)
Deprecated.void
setDiscountOverlaps(boolean v)
Deprecated.Sets whether overlap tokens (Tokens with 0 position increment) are ignored when computing norm.String
toString()
Deprecated.
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Constructor Detail
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LegacyBM25Similarity
public LegacyBM25Similarity()
Deprecated.BM25 with these default values:k1 = 1.2
b = 0.75
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LegacyBM25Similarity
public LegacyBM25Similarity(float k1, float b)
Deprecated.BM25 with the supplied parameter values.- Parameters:
k1
- Controls non-linear term frequency normalization (saturation).b
- Controls to what degree document length normalizes tf values.- Throws:
IllegalArgumentException
- ifk1
is infinite or negative, or ifb
is not within the range[0..1]
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Method Detail
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computeNorm
public long computeNorm(FieldInvertState state)
Deprecated.- Specified by:
computeNorm
in classSimilarity
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scorer
public Similarity.SimScorer scorer(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)
Deprecated.- Specified by:
scorer
in classSimilarity
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getK1
public final float getK1()
Deprecated.Returns thek1
parameter- See Also:
LegacyBM25Similarity(float, float)
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getB
public final float getB()
Deprecated.Returns theb
parameter- See Also:
LegacyBM25Similarity(float, float)
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setDiscountOverlaps
public void setDiscountOverlaps(boolean v)
Deprecated.Sets whether overlap tokens (Tokens with 0 position increment) are ignored when computing norm. By default this is true, meaning overlap tokens do not count when computing norms.
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getDiscountOverlaps
public boolean getDiscountOverlaps()
Deprecated.Returns true if overlap tokens are discounted from the document's length.- See Also:
setDiscountOverlaps(boolean)
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