Package org.elasticsearch.lucene.similarity

Class LegacyBM25Similarity

java.lang.Object
org.apache.lucene.search.similarities.Similarity
org.elasticsearch.lucene.similarity.LegacyBM25Similarity
@Deprecated public final class LegacyBM25Similarity extends org.apache.lucene.search.similarities.Similarity
Deprecated.
BM25Similarity should be used instead
Similarity that behaves like BM25Similarity while also applying the k1+1 factor to the numerator of the scoring formula
See Also:
  • BM25Similarity

  • Nested Class Summary

    Nested classes/interfaces inherited from class org.apache.lucene.search.similarities.Similarity

    org.apache.lucene.search.similarities.Similarity.SimScorer

  • Constructor Summary

    Constructors
    Constructor
    Description
    LegacyBM25Similarity()
    Deprecated.
    BM25 with these default values: k1 = 1.2 b = 0.75
    LegacyBM25Similarity(float k1, float b, boolean discountOverlaps)
    Deprecated.
    BM25 with the supplied parameter values.

  • Method Summary

    Modifier and Type
    Method
    Description
    long
    computeNorm(org.apache.lucene.index.FieldInvertState state)
    Deprecated.
     
    float
    getB()
    Deprecated.
    Returns the b parameter
    boolean
    getDiscountOverlaps()
    Deprecated.
    Returns true if overlap tokens are discounted from the document's length.
    float
    getK1()
    Deprecated.
    Returns the k1 parameter
    org.apache.lucene.search.similarities.Similarity.SimScorer
    scorer(float boost, org.apache.lucene.search.CollectionStatistics collectionStats, org.apache.lucene.search.TermStatistics... termStats)
    Deprecated.
     
    String
    toString()
    Deprecated.
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • LegacyBM25Similarity

      public LegacyBM25Similarity()
      Deprecated.
      BM25 with these default values:
      • k1 = 1.2
      • b = 0.75

    • LegacyBM25Similarity

      public LegacyBM25Similarity(float k1, float b, boolean discountOverlaps)
      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 - if k1 is infinite or negative, or if b is not within the range [0..1]

  • Method Details

    • computeNorm

      public long computeNorm(org.apache.lucene.index.FieldInvertState state)
      Deprecated.
      Specified by:
      computeNorm in class org.apache.lucene.search.similarities.Similarity

    • scorer

      public org.apache.lucene.search.similarities.Similarity.SimScorer scorer(float boost, org.apache.lucene.search.CollectionStatistics collectionStats, org.apache.lucene.search.TermStatistics... termStats)
      Deprecated.
      Specified by:
      scorer in class org.apache.lucene.search.similarities.Similarity

    • getK1

      public float getK1()
      Deprecated.
      Returns the k1 parameter

    • getB

      public float getB()
      Deprecated.
      Returns the b parameter

    • getDiscountOverlaps

      public boolean getDiscountOverlaps()
      Deprecated.
      Returns true if overlap tokens are discounted from the document's length.

    • toString

      public String toString()
      Deprecated.
      Overrides:
      toString in class Object