Package org.opensearch.index.rankeval

Class DiscountedCumulativeGain

java.lang.Object

org.opensearch.index.rankeval.DiscountedCumulativeGain

All Implemented Interfaces:

NamedWriteable, Writeable, ToXContent, ToXContentObject, EvaluationMetric

public class DiscountedCumulativeGain
extends Object
implements EvaluationMetric

Metric implementing Discounted Cumulative Gain. The `normalize` parameter can be set to calculate the normalized NDCG (set to false by default).
The optional `unknown_doc_rating` parameter can be used to specify a default rating for unlabeled documents.

See Also:

• Discounted Cumulative Gain
  

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	DiscountedCumulativeGain.Detail

Nested classes/interfaces inherited from interface org.opensearch.common.xcontent.ToXContent

ToXContent.DelegatingMapParams, ToXContent.MapParams, ToXContent.Params

Nested classes/interfaces inherited from interface org.opensearch.common.io.stream.Writeable

Writeable.Reader<V extends Object>, Writeable.Writer<V extends Object>

Field Summary

Fields

Modifier and Type	Field	Description
static final String	NAME

Fields inherited from interface org.opensearch.common.xcontent.ToXContent

EMPTY_PARAMS

Constructor Summary

Constructors

Constructor	Description
DiscountedCumulativeGain()
DiscountedCumulativeGain(boolean normalize, Integer unknownDocRating, int k)

Method Summary

Modifier and Type	Method	Description
final boolean	equals(Object obj)
EvalQueryQuality	evaluate(String taskId, SearchHit[] hits, List<RatedDocument> ratedDocs)	Evaluates a single ranking evaluation case.
OptionalInt	forcedSearchSize()	Metrics can define a size of the search hits windows they want to retrieve by overwriting this method.
static DiscountedCumulativeGain	fromXContent(XContentParser parser)
Integer	getUnknownDocRating()	get the rating used for unrated documents
String	getWriteableName()
final int	hashCode()
XContentBuilder	toXContent(XContentBuilder builder, ToXContent.Params params)
void	writeTo(StreamOutput out)

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.opensearch.index.rankeval.EvaluationMetric

combine

Methods inherited from interface org.opensearch.common.xcontent.ToXContentObject

isFragment

Field Details

NAME

public static final String NAME

See Also:

• Constant Field Values

Constructor Details

DiscountedCumulativeGain

public DiscountedCumulativeGain()

DiscountedCumulativeGain

public DiscountedCumulativeGain(boolean normalize,
 Integer unknownDocRating,
 int k)

Parameters:

normalize - If set to true, dcg will be normalized (ndcg) See https://en.wikipedia.org/wiki/Discounted_cumulative_gain

unknownDocRating - the rating for documents the user hasn't supplied an explicit rating for

k - the search window size all request use.

Method Details

writeTo

public void writeTo(StreamOutput out)
             throws IOException

Specified by:

writeTo in interface Writeable

Throws:

IOException

getWriteableName

public String getWriteableName()

Specified by:

getWriteableName in interface NamedWriteable

getUnknownDocRating

public Integer getUnknownDocRating()

get the rating used for unrated documents

forcedSearchSize

public OptionalInt forcedSearchSize()

Description copied from interface: EvaluationMetric

Metrics can define a size of the search hits windows they want to retrieve by overwriting this method. The default implementation returns an empty optional.

Specified by:

forcedSearchSize in interface EvaluationMetric

Returns:

the number of search hits this metrics requests

evaluate

public EvalQueryQuality evaluate(String taskId,
 SearchHit[] hits,
 List<RatedDocument> ratedDocs)

Description copied from interface: EvaluationMetric

Evaluates a single ranking evaluation case.

Specified by:

evaluate in interface EvaluationMetric

Parameters:

taskId - an identifier of the query for which the search ranking is evaluated

hits - the search result hits

ratedDocs - the documents that contain the document rating for this query case

Returns:

an EvalQueryQuality instance that contains the metric score with respect to the provided search hits and ratings

fromXContent

public static DiscountedCumulativeGain fromXContent(XContentParser parser)

toXContent

public XContentBuilder toXContent(XContentBuilder builder,
 ToXContent.Params params)
                           throws IOException

Specified by:

toXContent in interface ToXContent

Throws:

IOException

equals

public final boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public final int hashCode()

Overrides:

hashCode in class Object