Package net.sf.tweety.logics.rcl.semantics

Class RelationalRankingFunction

  • All Implemented Interfaces:
    net.sf.tweety.commons.Interpretation<RclBeliefSet,​RelationalConditional>
    public class RelationalRankingFunction
extends net.sf.tweety.commons.AbstractInterpretation<RclBeliefSet,​RelationalConditional>
    A relational ranking function (or relational ordinal conditional function, ROCF) that maps Herbrand interpretations to integers.

    See W. Spohn. Ordinal conditional functions: a dynamic theory of epistemic states. In W.L. Harper and B. Skyrms, editors, Causation in Decision, Belief Change, and Statistics, II, pages 105-134. Kluwer Academic Publishers, 1988.

    See also [Kern-Isberner,Thimm, "A Ranking Semantics for Relational Defaults", in preparation].
    Author:
    Matthias Thimm

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static Integer INFINITY
      Integer used to define infinity.

    • Constructor Summary

      Constructors 
      Constructor Description
      RelationalRankingFunction​(net.sf.tweety.logics.fol.syntax.FolSignature signature)
      Creates a new ranking function mapping each given interpretation to zero.

    • Field Detail

      • INFINITY

        public static final Integer INFINITY
        Integer used to define infinity.

    • Constructor Detail

      • RelationalRankingFunction

        public RelationalRankingFunction​(net.sf.tweety.logics.fol.syntax.FolSignature signature)
        Creates a new ranking function mapping each given interpretation to zero.
        Parameters:
        signature - the signature of the language this ranking function is defined on.

    • Method Detail

      • rank

        public Integer rank​(net.sf.tweety.logics.fol.semantics.HerbrandInterpretation w)
             throws IllegalArgumentException
        Gets the rank of the given Herbrand interpretation.
        Parameters:
        w - a Herbrand interpretation.
        Returns:
        the rank of the given Herbrand interpretation.
        Throws:
        IllegalArgumentException - if the given Herbrand interpretation has no rank in this ranking function.

      • setRank

        public void setRank​(net.sf.tweety.logics.fol.semantics.HerbrandInterpretation w,
                    Integer value)
        Sets the rank for the given Herbrand interpretation.
        Parameters:
        w - a Herbrand interpretation.
        value - the rank for the Herbrand interpretation.

      • rank

        public Integer rank​(net.sf.tweety.logics.fol.syntax.FolFormula formula)
             throws IllegalArgumentException
        Gets the rank of the given sentence (ground formula). Throws an IllegalArgumentException when the language of the formula does not correspond to the language of the interpretations this ranking function is defined on or the formula is not a sentence. Otherwise the rank of a formula is defined as the minimal rank of its satisfying interpretations.
        Parameters:
        formula - a formula.
        Returns:
        the rank of the given formula.
        Throws:
        IllegalArgumentException - if the languages of the formula does not correspond to the language of the interpretations this ranking function is defined on or the formula is not a sentence.

      • normalize

        public void normalize()
        Normalizes this OCF, i.e. appropriately shifts the ranks such that the minimal rank equals zero.

      • getPossibleInterpretations

        public Set<net.sf.tweety.logics.fol.semantics.HerbrandInterpretation> getPossibleInterpretations()
        Returns all interpretations that are mapped to a rank unequal to INFINITY.
        Returns:
        all interpretations that are mapped to a rank unequal to INFINITY.

      • numFalsifiedInstances

        public Integer numFalsifiedInstances​(net.sf.tweety.logics.fol.semantics.HerbrandInterpretation w,
                                     RelationalConditional rc)
        Returns the number of instances of "rc" that are falsified by the given interpretation.
        Parameters:
        w - a Herbrand interpretation.
        rc - a relational conditional.
        Returns:
        the number of instances of "rc" that are falsified by the given interpretation.

      • numVerifiedInstances

        public Integer numVerifiedInstances​(net.sf.tweety.logics.fol.semantics.HerbrandInterpretation w,
                                    RelationalConditional rc)
        Returns the number of instances of "rc" that are verified by the given interpretation.
        Parameters:
        w - a Herbrand interpretation.
        rc - a relational conditional.
        Returns:
        the number of instances of "rc" that are verified by the given interpretation.