org.apache.lucene.search

Class DefaultSimilarity

Implemented Interfaces:
Serializable

public class DefaultSimilarity
extends Similarity

Expert: Default scoring implementation.

Method Summary

float
coord(int overlap, int maxOverlap)
Implemented as overlap / maxOverlap.
float
idf(int docFreq, int numDocs)
Implemented as log(numDocs/(docFreq+1)) + 1.
float
lengthNorm(String fieldName, int numTerms)
Implemented as 1/sqrt(numTerms).
float
queryNorm(float sumOfSquaredWeights)
Implemented as 1/sqrt(sumOfSquaredWeights).
float
sloppyFreq(int distance)
Implemented as 1 / (distance + 1).
float
tf(float freq)
Implemented as sqrt(freq).

Methods inherited from class org.apache.lucene.search.Similarity

coord, decodeNorm, encodeNorm, getDefault, getNormDecoder, idf, idf, idf, lengthNorm, queryNorm, setDefault, sloppyFreq, tf, tf

Method Details

coord

public float coord(int overlap,
                   int maxOverlap)
Implemented as overlap / maxOverlap.
Overrides:
coord in interface Similarity

idf

public float idf(int docFreq,
                 int numDocs)
Implemented as log(numDocs/(docFreq+1)) + 1.
Overrides:
idf in interface Similarity

lengthNorm

public float lengthNorm(String fieldName,
                        int numTerms)
Implemented as 1/sqrt(numTerms).
Overrides:
lengthNorm in interface Similarity

queryNorm

public float queryNorm(float sumOfSquaredWeights)
Implemented as 1/sqrt(sumOfSquaredWeights).
Overrides:
queryNorm in interface Similarity

sloppyFreq

public float sloppyFreq(int distance)
Implemented as 1 / (distance + 1).
Overrides:
sloppyFreq in interface Similarity

tf

public float tf(float freq)
Implemented as sqrt(freq).
Overrides:
tf in interface Similarity

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