net.sf.tweety.logics.rcl.semantics

Class RelationalRankingFunction

java.lang.Object

net.sf.tweety.commons.AbstractInterpretation

net.sf.tweety.logics.rcl.semantics.RelationalRankingFunction

All Implemented Interfaces:

Interpretation

public class RelationalRankingFunction
extends AbstractInterpretation

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 and Description
static java.lang.Integer	INFINITY Integer used to define infinity.
private java.util.Map<HerbrandInterpretation,java.lang.Integer>	ranks The ranks of the Herbrand interpretations.
private FolSignature	signature The signature of the language this ranking function is defined on.

Constructor Summary

Constructors

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

Method Summary

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

Methods inherited from class net.sf.tweety.commons.AbstractInterpretation

satisfies

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

INFINITY

public static final java.lang.Integer INFINITY

Integer used to define infinity.

ranks

private java.util.Map<HerbrandInterpretation,java.lang.Integer> ranks

The ranks of the Herbrand interpretations.

signature

private FolSignature signature

The signature of the language this ranking function is defined on.

Constructor Detail

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 Detail

rank

public java.lang.Integer rank(HerbrandInterpretation w)
                       throws java.lang.IllegalArgumentException

Gets the rank of the given Herbrand interpretation.

Parameters:

w - a Herbrand interpretation.

Returns:

the rank of the given Herbrand interpretation.

Throws:

java.lang.IllegalArgumentException - if the given Herbrand interpretation has no rank in this ranking function.

setRank

public void setRank(HerbrandInterpretation w,
                    java.lang.Integer value)

Sets the rank for the given Herbrand interpretation.

Parameters:

w - a Herbrand interpretation.

value - the rank for the Herbrand interpretation.

rank

public java.lang.Integer rank(FolFormula formula)
                       throws java.lang.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:

java.lang.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(Formula formula)
                  throws java.lang.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:

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

getWeakPrototypes

private java.util.Set<RelationalConditional> getWeakPrototypes(RelationalConditional rc)

Returns the set of instances with weak prototypes.

Parameters:

rc - a relational conditional

Returns:

the set of instances with weak prototypes.

getPrototypes

private java.util.Set<RelationalConditional> getPrototypes(RelationalConditional rc)

Returns the set of instances with prototypes.

Parameters:

rc - a relational conditional

Returns:

the set of instances with prototypes.

satisfies

public boolean satisfies(BeliefBase beliefBase)
                  throws java.lang.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:

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

minimalRank

private java.lang.Integer minimalRank()

Returns the minimal rank of this OCF.

Returns:

the minimal rank of this OCF.

normalize

public void normalize()

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

getPossibleInterpretations

public java.util.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 java.lang.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 java.lang.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 java.lang.String toString()

Overrides:

toString in class java.lang.Object