Package org.terrier.matching.models

Class TF_IDF

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, Model
    public class TF_IDF
extends WeightingModel
    This class implements the TF_IDF weighting model. tf is given by Robertson's tf and idf is given by the standard Sparck Jones' idf [Sparck Jones, 1972].
    Author:
    Ben He, Gianni Amati, Vassilis Plachouras
    See Also:
    Serialized Form

    • Constructor Detail

      • TF_IDF

        public TF_IDF()
        A default constructor to make this model.

      • TF_IDF

        public TF_IDF​(double _b)
        Constructs an instance of TF_IDF
        Parameters:
        _b -

    • Method Detail

      • getInfo

        public final java.lang.String getInfo()
        Returns the name of the model, in this case "TF_IDF"
        Specified by:
        getInfo in interface Model
        Specified by:
        getInfo in class WeightingModel
        Returns:
        the name of the model

      • score

        public final double score​(double tf,
                          double docLength)
        Uses TF_IDF to compute a weight for a term in a document.
        Specified by:
        score in class WeightingModel
        Parameters:
        tf - The term frequency of the term in the document
        docLength - the document's length
        Returns:
        the score assigned to a document with the given tf and docLength, and other preset parameters

      • setParameter

        public void setParameter​(double _b)
        Sets the b parameter to ranking formula
        Specified by:
        setParameter in interface Model
        Overrides:
        setParameter in class WeightingModel
        Parameters:
        _b - the b parameter value to use.

      • getParameter

        public double getParameter()
        Returns the b parameter to the ranking formula as set by setParameter()
        Specified by:
        getParameter in interface Model
        Overrides:
        getParameter in class WeightingModel