Package org.tweetyproject.logics.rcl.semantics

Class RelationalRankingFunction

java.lang.Object

org.tweetyproject.commons.AbstractInterpretation<RclBeliefSet,RelationalConditional>

org.tweetyproject.logics.rcl.semantics.RelationalRankingFunction

All Implemented Interfaces:

Interpretation<RclBeliefSet,RelationalConditional>

public class RelationalRankingFunction
extends 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 final Integer	INFINITY	Integer used to define infinity.

Constructor Summary

Constructors

Constructor	Description
RelationalRankingFunction(FolSignature signature)	Creates a new ranking function mapping each given interpretation to zero.

Method Summary

Modifier and Type	Method	Description
Set<HerbrandInterpretation>	getPossibleInterpretations()	Returns all interpretations that are mapped to a rank unequal to INFINITY.
void	normalize()	Normalizes this OCF, i.e.
Integer	numFalsifiedInstances(HerbrandInterpretation w, RelationalConditional rc)	Returns the number of instances of "rc" that are falsified by the given interpretation.
Integer	numVerifiedInstances(HerbrandInterpretation w, RelationalConditional rc)	Returns the number of instances of "rc" that are verified by the given interpretation.
Integer	rank(HerbrandInterpretation w)	Gets the rank of the given Herbrand interpretation.
Integer	rank(FolFormula formula)	Gets the rank of the given sentence (ground formula).
boolean	satisfies(RclBeliefSet beliefBase)	Checks whether this interpretation satisfies the given knowledge base.
boolean	satisfies(RelationalConditional formula)	Checks whether this interpretation satisfies the given formula.
void	setRank(HerbrandInterpretation w, Integer value)	Sets the rank for the given Herbrand interpretation.
String	toString()

Methods inherited from class org.tweetyproject.commons.AbstractInterpretation

satisfies

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

INFINITY

public static final Integer INFINITY

Integer used to define infinity.

Constructor Details

RelationalRankingFunction

public RelationalRankingFunction(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 Details

rank

public Integer rank(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(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(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.

satisfies

public boolean satisfies(RelationalConditional formula)
                  throws IllegalArgumentException

Description copied from interface: Interpretation

Checks whether this interpretation satisfies the given formula.

Parameters:

formula - a formula .

Returns:

"true" if this interpretation satisfies the given formula.

Throws:

IllegalArgumentException - if the formula does not correspond to the expected language.

satisfies

public boolean satisfies(RclBeliefSet beliefBase)
                  throws IllegalArgumentException

Description copied from interface: Interpretation

Checks whether this interpretation satisfies the given knowledge base.

Parameters:

beliefBase - a knowledge base.

Returns:

"true" if this interpretation satisfies the given knowledge base.

Throws:

IllegalArgumentException - IllegalArgumentException if the knowledgebase does not correspond to the expected language.

normalize

public void normalize()

Normalizes this OCF, i.e. appropriately shifts the ranks such that the minimal rank equals zero.

getPossibleInterpretations

public Set<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(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(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.

toString

public String toString()

Overrides:

toString in class Object