Class CustomScoreProvider

An instance of this subclass should be returned by GetCustomScoreProvider(AtomicReaderContext), if you want to modify the custom score calculation of a CustomScoreQuery.

Since Lucene 2.9, queries operate on each segment of an index separately, so the protected m_context field can be used to resolve doc IDs, as the supplied doc ID is per-segment and without knowledge of the Lucene.Net.Index.IndexReader you cannot access the document or Lucene.Net.Search.IFieldCache.

Note

This API is experimental and might change in incompatible ways in the next release.

@since 2.9.2

Inheritance

object

CustomScoreProvider

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Lucene.Net.Queries

Assembly: Lucene.Net.Queries.dll

Syntax

public class CustomScoreProvider

Constructors

CustomScoreProvider(AtomicReaderContext)

Creates a new instance of the provider class for the given Lucene.Net.Index.IndexReader.

Declaration

public CustomScoreProvider(AtomicReaderContext context)

Parameters

Type	Name	Description
AtomicReaderContext	context

Fields

m_context

An instance of this subclass should be returned by GetCustomScoreProvider(AtomicReaderContext), if you want to modify the custom score calculation of a CustomScoreQuery.

Since Lucene 2.9, queries operate on each segment of an index separately, so the protected m_context field can be used to resolve doc IDs, as the supplied doc ID is per-segment and without knowledge of the Lucene.Net.Index.IndexReader you cannot access the document or Lucene.Net.Search.IFieldCache.

Note

This API is experimental and might change in incompatible ways in the next release.

@since 2.9.2

Declaration

protected readonly AtomicReaderContext m_context

Field Value

Type	Description
AtomicReaderContext

Methods

CustomExplain(int, Explanation, Explanation)

Explain the custom score. Whenever overriding CustomScore(int, float, float), this method should also be overridden to provide the correct explanation for the part of the custom scoring.

Declaration

public virtual Explanation CustomExplain(int doc, Explanation subQueryExpl, Explanation valSrcExpl)

Parameters

Type	Name	Description
int	doc	doc being explained.
Explanation	subQueryExpl	explanation for the sub-query part.
Explanation	valSrcExpl	explanation for the value source part.

Returns

Type	Description
Explanation	an explanation for the custom score

CustomExplain(int, Explanation, Explanation[])

Explain the custom score. Whenever overriding CustomScore(int, float, float[]), this method should also be overridden to provide the correct explanation for the part of the custom scoring.

Declaration

public virtual Explanation CustomExplain(int doc, Explanation subQueryExpl, Explanation[] valSrcExpls)

Parameters

Type	Name	Description
int	doc	doc being explained.
Explanation	subQueryExpl	explanation for the sub-query part.
Explanation[]	valSrcExpls	explanation for the value source part.

Returns

Type	Description
Explanation	an explanation for the custom score

CustomScore(int, float, float)

Compute a custom score by the subQueryScore and the FunctionQuery score.

Subclasses can override this method to modify the custom score.

If your custom scoring is different than the default herein you should override at least one of the two CustomScore(int, float, float) methods. If the number of FunctionQuerys is always < 2 it is sufficient to override this CustomScore(int, float, float) method, which is simpler.

The default computation herein is a multiplication of the two scores:

ModifiedScore = subQueryScore * valSrcScore

Declaration

public virtual float CustomScore(int doc, float subQueryScore, float valSrcScore)

Parameters

Type	Name	Description
int	doc	id of scored doc.
float	subQueryScore	score of that doc by the subQuery.
float	valSrcScore	score of that doc by the FunctionQuery.

Returns

Type	Description
float	custom score.

CustomScore(int, float, float[])

Compute a custom score by the subQuery score and a number of FunctionQuery scores.

Subclasses can override this method to modify the custom score.

If your custom scoring is different than the default herein you should override at least one of the two CustomScore(int, float, float) methods. If the number of FunctionQuerys is always < 2 it is sufficient to override the other CustomScore(int, float, float) method, which is simpler.

The default computation herein is a multiplication of given scores:

ModifiedScore = valSrcScore * valSrcScores[0] * valSrcScores[1] * ...

Declaration

public virtual float CustomScore(int doc, float subQueryScore, float[] valSrcScores)

Parameters

Type	Name	Description
int	doc	id of scored doc.
float	subQueryScore	score of that doc by the subQuery.
float[]	valSrcScores	scores of that doc by the FunctionQuery.

Returns

Type	Description
float	custom score.