Class MRFDependenceScoreModifier

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

    public class MRFDependenceScoreModifier
    extends DependenceScoreModifier
    Implements Markov Random Fields. See Metzler & Croft, SIGIR 2005. Note that this implementation does not utilise the frequency of a tuple in the collection - instead, this is assumed to be a constant, as per the implementation in the Ivory retrieval system. Properties:
    • See properties for DependenceScoreModifier
    • mrf.mu - Mu of MRF model, in the Dirichlet model.
    References: Metzler, D. and Croft, W.B., "A Markov Random Field Model for Term Dependencies," Proceedings of the 28th annual international ACM SIGIR conference on Research and development in information retrieval (SIGIR 2005), 472-479, 2005
    Since:
    3.0
    Author:
    Craig Macdonald
    • Field Detail

      • MU

        protected double MU
    • Constructor Detail

      • MRFDependenceScoreModifier

        public MRFDependenceScoreModifier()
    • Method Detail

      • modifyScores

        public boolean modifyScores​(Index index,
                                    MatchingQueryTerms terms,
                                    ResultSet set)
        Modifies the scores of documents, in which there exist, or there does not exist a given phrase.
        Specified by:
        modifyScores in interface DocumentScoreModifier
        Overrides:
        modifyScores in class DependenceScoreModifier
        Parameters:
        index - Index the data structures to use.
        terms - MatchingQueryTerms the terms to be matched for the query. This does not correspond to the phrase terms necessarily, but to all the terms of the query.
        set - ResultSet the result set for the query.
        Returns:
        true if any scores have been altered