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<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 Details

    • ClingoSolver

      public ClingoSolver(String pathToClingo, Shell bash)
      Constructs a new instance pointing to a specific Clingo solver. The maximum number of models that Clingo will compute is set to the default value (see ASPSolver.maxNumOfModels).
      Parameters:
      pathToClingo - binary location of Clingo on the hard drive. The given location has to contain a binary called "clingo". Do not include the binary itself in the path.
      bash - shell to run commands

    • ClingoSolver

      public ClingoSolver(String pathToClingo)
      Constructs a new instance pointing to a specific Clingo solver. The maximum number of models that Clingo will compute is set to the default value (see ASPSolver.maxNumOfModels).
      Parameters:
      pathToClingo - binary location of Clingo on the hard drive. The given location has to contain a binary called "clingo". Do not include the binary itself in the path.

    • ClingoSolver

      public ClingoSolver(String pathToClingo, int maxNOfModels)
      Constructs a new instance pointing to a specific Clingo solver.
      Parameters:
      pathToClingo - binary location of Clingo on the hard drive. The given location has to contain a binary called "clingo". Do not include the binary itself in the path.
      maxNOfModels - the maximum number of models that Clingo will compute. Set it to 0 if you want all models.

  • Method Details

    • getOptimumString

      public 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 - SolverException

    • getOptimum

      public List<Integer> getOptimum(String p)
      Parameters:
      p - problem to be solved
      Returns:
      optima

    • 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.

    • getModels

      public 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

    • getModels

      public List<AnswerSet> getModels(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 List<AnswerSet> getModels(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

    • getOptimum

      public List<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

    • query

      public Boolean query(Program beliefbase, ASPLiteral formula)
      Description copied from interface: QualitativeReasoner
      Queries the given belief base with the provided formula and returns a boolean result. The result indicates whether the formula is entailed or satisfied by the belief base according to the qualitative reasoning method implemented by the reasoner.
      Specified by:
      query in interface QualitativeReasoner<Program,ASPLiteral>
      Specified by:
      query in interface Reasoner<Boolean,Program,ASPLiteral>
      Specified by:
      query in class ASPSolver
      Parameters:
      beliefbase - The belief base to be queried.
      formula - The formula for which the query is made.
      Returns:
      `TRUE` if the formula is entailed or satisfied by the belief base, `FALSE` otherwise.

    • query

      public Boolean query(Program beliefbase, ASPLiteral formula, InferenceMode inferenceMode)
      Evaluates a query on the given belief base using the specified inference mode.

      This method checks whether the given formula is entailed by the belief base under the specified inference mode. It retrieves the answer sets of the belief base and checks the presence of the formula in these sets based on the chosen inference mode, either skeptical or credulous.

      Parameters:
      beliefbase - The program representing the belief base to query.
      formula - The formula (literal) to be checked within the answer sets.
      inferenceMode - The mode of inference, either skeptical or credulous.
      Returns:
      true if the formula is entailed by the belief base under the specified inference mode, false otherwise.

    • 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(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

    • setPathToClingo

      public void setPathToClingo(String path)
      Sets the location of the Clingo solver on the hard drive.
      Parameters:
      path - path to Clingo

    • isInstalled

      public boolean isInstalled()
      Description copied from interface: QualitativeReasoner
      Checks whether the underlying solver or reasoning mechanism used by this reasoner is installed and available for use. This can be helpful when the reasoner depends on external tools or libraries for performing the reasoning tasks.
      Returns:
      `true` if the solver is installed and available, `false` otherwise.