Package org.sosy_lab.java_smt.api

Interface OptimizationProverEnvironment

All Superinterfaces:
AutoCloseable, BasicProverEnvironment<Void>
All Known Implementing Classes:
DebuggingOptimizationProverEnvironment
public interface OptimizationProverEnvironment extends BasicProverEnvironment<Void>, AutoCloseable
Interface for optimization modulo SMT.

  • Method Details

    • maximize

      int maximize(Formula objective)
      Add the maximization objective.

      Note: push/pop may be used for switching objectives

      Returns:
      Objective handle, to be used for retrieving the value.

    • minimize

      int minimize(Formula objective)
      Add minimization objective.

      Note: push/pop may be used for switching objectives

      Returns:
      Objective handle, to be used for retrieving the value.

    • check

      OptimizationProverEnvironment.OptStatus check() throws InterruptedException, SolverException
      Optimize the objective function subject to the previously imposed constraints.
      Returns:
      Status of the optimization problem.
      Throws:
      InterruptedException
      SolverException

    • upper

      Optional<Rational> upper(int handle, Rational epsilon)
      Parameters:
      epsilon - Value to substitute for the epsilon.
      Returns:
      Upper approximation of the optimized value, or absent optional if the objective is unbounded.

    • lower

      Optional<Rational> lower(int handle, Rational epsilon)
      Parameters:
      epsilon - Value to substitute for the epsilon.
      Returns:
      Lower approximation of the optimized value, or absent optional if the objective is unbounded.

    • getModel

      Model getModel() throws SolverException
      Get a satisfying assignment. This method should be called only immediately after an BasicProverEnvironment.isUnsat() call that returned false. The returned model is guaranteed to stay constant and valid as long as the solver context is available, even if constraints are added to, pushed or popped from the prover stack.

      A model might contain additional symbols with their evaluation, if a solver uses its own temporary symbols. There should be at least a value-assignment for each free symbol.

      Please note that the prover is allowed to use standard numbers for any real variable in the model after a sat-query returned OptimizationProverEnvironment.OptStatus.OPT. For integer formulas, we expect the optimal assignment.

      Example 1: For the constraint 'x<10' with a real x, the upper bound of x is '10-epsilon' (epsilon can even be set to zero). The model can return the assignment x=9. To get an optimal assignment, query the solver with an additional constraint 'x == 10-epsilon'.

      Example 2: For the constraint 'x<10' with an integer x, the upper bound of x is '9' (epsilon is irrelevant here and can be zero). The model returns the optimal assignment x=9.

      Specified by:
      getModel in interface BasicProverEnvironment<Void>
      Throws:
      SolverException