Class DFRee

  • All Implemented Interfaces:, java.lang.Cloneable, Model

    public class DFRee
    extends WeightingModel
    This class implements the DFRee weighting model. DFRee stands for DFR free from parameters. In particular, the DFRee model computes an average number of extra bits (as information divergence) that are necessary to code one extra token of the query term with respect to the probability distribution observed in the document. There are two possible populations to sample the probability distribution: considering only the document and no other document in the colection, or the document considered as sample drawn from the entire collection statistics. DFRee takes an average of these two information measures, that is their inner product.
    Gianni Amati
    See Also:
    Serialized Form
    • Constructor Detail

      • DFRee

        public DFRee()
        A default constructor to make this model.
    • Method Detail

      • getInfo

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

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