Package org.elasticsearch.index.rankeval

Class DiscountedCumulativeGain

java.lang.Object
org.elasticsearch.index.rankeval.DiscountedCumulativeGain
All Implemented Interfaces:
org.elasticsearch.common.io.stream.NamedWriteable, org.elasticsearch.common.io.stream.Writeable, EvaluationMetric, org.elasticsearch.xcontent.ToXContent, org.elasticsearch.xcontent.ToXContentObject
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:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static final class 
    DiscountedCumulativeGain.Detail
     

    Nested classes/interfaces inherited from interface org.elasticsearch.xcontent.ToXContent

    org.elasticsearch.xcontent.ToXContent.DelegatingMapParams, org.elasticsearch.xcontent.ToXContent.MapParams, org.elasticsearch.xcontent.ToXContent.Params

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

    org.elasticsearch.common.io.stream.Writeable.Reader<V extends Object>, org.elasticsearch.common.io.stream.Writeable.Writer<V extends Object>

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    NAME
     

    Fields inherited from interface org.elasticsearch.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, org.elasticsearch.search.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(org.elasticsearch.xcontent.XContentParser parser)
     
    Integer
    getUnknownDocRating()
    get the rating used for unrated documents
    String
    getWriteableName()
     
    final int
    hashCode()
     
    org.elasticsearch.xcontent.XContentBuilder
    toXContent(org.elasticsearch.xcontent.XContentBuilder builder, org.elasticsearch.xcontent.ToXContent.Params params)
     
    void
    writeTo(org.elasticsearch.common.io.stream.StreamOutput out)
     

    Methods inherited from class java.lang.Object

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

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

    combine

    Methods inherited from interface org.elasticsearch.xcontent.ToXContentObject

    isFragment

  • Field Details

  • 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(org.elasticsearch.common.io.stream.StreamOutput out) throws IOException
      Specified by:
      writeTo in interface org.elasticsearch.common.io.stream.Writeable
      Throws:
      IOException

    • getWriteableName

      public String getWriteableName()
      Specified by:
      getWriteableName in interface org.elasticsearch.common.io.stream.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, org.elasticsearch.search.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(org.elasticsearch.xcontent.XContentParser parser)

    • toXContent

      public org.elasticsearch.xcontent.XContentBuilder toXContent(org.elasticsearch.xcontent.XContentBuilder builder, org.elasticsearch.xcontent.ToXContent.Params params) throws IOException
      Specified by:
      toXContent in interface org.elasticsearch.xcontent.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