Package org.tweetyproject.lp.asp.reasoner

Class ClingoSolver

java.lang.Object

org.tweetyproject.lp.asp.reasoner.ASPSolver

org.tweetyproject.lp.asp.reasoner.ClingoSolver

All Implemented Interfaces:

ModelProvider<ASPRule,Program,AnswerSet>, QualitativeReasoner<Program,ASPLiteral>, Reasoner<java.lang.Boolean,Program,ASPLiteral>

public class ClingoSolver
extends ASPSolver

Invokes Clingo (Part of the Potassco project), an ASP system that grounds and solves logic programs, and returns computed answer sets.

Author:

Nils Geilen, Matthias Thimm, Anna Gessler

Constructor Summary

Constructors

Constructor	Description
ClingoSolver(java.lang.String path2clingo)	Constructs a new instance pointing to specific a Clingo solver.
ClingoSolver(java.lang.String path2clingo, Shell bash)	Constructs a new instance pointing to a specific Clingo solver.

Method Summary

Modifier and Type	Method	Description
AnswerSet	getModel(Program p)	Returns a single (dedicated) model of the given belief base.
java.util.List<AnswerSet>	getModels(java.io.File file)	Returns a characterizing model (answer set) of the given belief base.
java.util.List<AnswerSet>	getModels(java.lang.String s)	Returns a characterizing model (answer set) of the given belief base.
java.util.List<AnswerSet>	getModels(Program p)	Returns a characterizing model of the given belief base
java.util.List<java.lang.Integer>	getOptimum(Program p)	Computes the optimum of a program that contains optimization statements, if there is one.
java.lang.String	getOptimumString()	Returns the optimum of the previously solved program, if there is one.
java.lang.Boolean	query(Program beliefbase, ASPLiteral formula)	Queries the given belief base for the given formula.
java.lang.Boolean	query(Program beliefbase, ASPLiteral formula, InferenceMode inferenceMode)
void	setOptions(java.lang.String options)	Set the command line options for Clingo.
void	setPathToDLV(java.lang.String path)	Sets the location of the Clingo solver on the hard drive.
void	toggleOutputWhitelist(boolean b)	Activates or deactivates the option to use a whitelist of predicates.

Methods inherited from class org.tweetyproject.lp.asp.reasoner.ASPSolver

getIntegerMaximum, getMaxNumOfModels, getModel, getModels, getOutput, setIntegerMaximum, setMaxNumOfModels

Methods inherited from class java.lang.Object

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

Constructor Detail

ClingoSolver

public ClingoSolver(java.lang.String path2clingo,
                    Shell bash)

Constructs a new instance pointing to a specific Clingo solver.

Parameters:

path2clingo - binary location of Clingo on the hard drive

bash - shell to run commands

ClingoSolver

public ClingoSolver(java.lang.String path2clingo)

Constructs a new instance pointing to specific a Clingo solver.

Parameters:

path2clingo - binary location of Clingo on the hard drive

Method Detail

getOptimumString

public java.lang.String getOptimumString()
                                  throws SolverException

Returns the optimum of the previously solved program, if there is one.

Returns:

optimum of previously solved program in string format, i.e. numbers separated by spaces

Throws:

SolverException

getModels

public java.util.List<AnswerSet> getModels(Program p)

Description copied from interface: ModelProvider

Returns a characterizing model of the given belief base

Specified by:

getModels in interface ModelProvider<ASPRule,Program,AnswerSet>

Specified by:

getModels in class ASPSolver

Parameters:

p - some belief base

Returns:

the (selected) models of the belief base

getOptimum

public java.util.List<java.lang.Integer> getOptimum(Program p)

Computes the optimum of a program that contains optimization statements, if there is one. Note: This methods calculates only the optimum and returns no answer sets.

Parameters:

p - ASP program

Returns:

list of calculated optima

getModels

public java.util.List<AnswerSet> getModels(java.lang.String s)

Description copied from class: ASPSolver

Returns a characterizing model (answer set) of the given belief base.

Specified by:

getModels in class ASPSolver

Parameters:

s - containing belief base

Returns:

AnswerSet

getModels

public java.util.List<AnswerSet> getModels(java.io.File file)

Description copied from class: ASPSolver

Returns a characterizing model (answer set) of the given belief base.

Specified by:

getModels in class ASPSolver

Parameters:

file - containing belief base

Returns:

AnswerSet

query

public java.lang.Boolean query(Program beliefbase,
                               ASPLiteral formula)

Description copied from interface: Reasoner

Queries the given belief base for the given formula.

Specified by:

query in interface QualitativeReasoner<Program,ASPLiteral>

Specified by:

query in interface Reasoner<java.lang.Boolean,Program,ASPLiteral>

Specified by:

query in class ASPSolver

Parameters:

beliefbase - a belief base

formula - a formula

Returns:

the answer to the query

query

public java.lang.Boolean query(Program beliefbase,
                               ASPLiteral formula,
                               InferenceMode inferenceMode)

getModel

public AnswerSet getModel(Program p)

Description copied from interface: ModelProvider

Returns a single (dedicated) model of the given belief base. If the implemented method allows for more than one dedicated model, the selection may be non-deterministic.

Parameters:

p - some belief base

Returns:

a selected model of the belief base.

toggleOutputWhitelist

public void toggleOutputWhitelist(boolean b)

Activates or deactivates the option to use a whitelist of predicates. If activated, answer sets will only contain atoms over predicates that are part of the whitelist. This corresponds to the #show statement of the clingo input language.

Parameters:

b - whether to use a whitelist of predicate

setOptions

public void setOptions(java.lang.String options)

Set the command line options for Clingo.

Parameters:

options - a string of options in the correct format, e.g. in the form "--opt" and separated by spaces

setPathToDLV

public void setPathToDLV(java.lang.String path)

Sets the location of the Clingo solver on the hard drive.

Parameters:

path - path to Clingo