Package org.sosy_lab.java_smt.api

Interface InterpolatingProverEnvironment<T>

    • Method Detail

      • getInterpolant

        BooleanFormula getInterpolant​(Collection<T> formulasOfA)
                       throws SolverException,
                              InterruptedException
        Get an interpolant for two groups of formulas. This should be called only immediately after an BasicProverEnvironment.isUnsat() call that returned true.

        There is no direct guarantee that the interpolants returned are part of an inductive sequence', however this seems to work for most (all?) solvers as long as the same proof is used, i.e. all interpolants are computed after the same SAT-check.

        Parameters:
        formulasOfA - A collection of values returned by BasicProverEnvironment.push(BooleanFormula). All the corresponding formulas from group A, the remaining formulas form group B.
        Returns:
        An interpolant for A and B
        Throws:
        SolverException - if interpolant cannot be computed, for example because interpolation procedure is incomplete
        InterruptedException

      • getSeqInterpolants

        default List<BooleanFormula> getSeqInterpolants​(List<? extends Collection<T>> partitionedFormulas)
                                         throws SolverException,
                                                InterruptedException
        This method returns interpolants of an 'inductive sequence'. This property must be supported by the interpolation-strategy of the underlying SMT-solver! Depending on the underlying SMT-solver this method might be faster than N direct calls to getInterpolant().

        The prover stack should contain the partitioned formulas, but any order is allowed. For an input of N partitions we return N-1 interpolants. Any asserted formula that is on the prover stack and not part of the partitioned list, will be used for background theory and its symbols can appear in any interpolant.

        Returns:
        a 'inductive sequence' of interpolants, such that the implication AND(I_i, P_i) => I_(i+1) is satisfied for all i, where P_i is the conjunction of all formulas in partition i.
        Throws:
        SolverException - if interpolant cannot be computed, for example because interpolation procedure is incomplete
        InterruptedException

      • getTreeInterpolants

        List<BooleanFormula> getTreeInterpolants​(List<? extends Collection<T>> partitionedFormulas,
                                         int[] startOfSubTree)
                                  throws SolverException,
                                         InterruptedException
        Compute a sequence of interpolants. The nesting array describes the start of the subtree for tree interpolants. For inductive sequences of interpolants use a nesting array completely filled with 0.

        Example: 

         A  D
 |  |
 B  E
 | /
 C
 |
 F  H
 | /
 G

 arrayIndex     = [0,1,2,3,4,5,6,7]  // only for demonstration, not needed
 partition      = [A,B,D,E,C,F,H,G]  // post-order of tree
 startOfSubTree = [0,0,2,2,0,0,6,0]  // index of left-most leaf of the current element

        The prover stack should contain the partitioned formulas. For an input of N partitions (nodes in the tree) we return N-1 interpolants (one interpolant for/below each node except the root). Any asserted formula that is on the prover stack and not part of the partitioned list, will be used for background theory and its symbols can appear in any interpolant.

        Parameters:
        partitionedFormulas - of formulas
        startOfSubTree - The start of the subtree containing the formula at this index as root.
        Returns:
        Tree interpolants respecting the nesting relation.
        Throws:
        SolverException - if interpolant cannot be computed, for example because interpolation procedure is incomplete
        InterruptedException

      • checkTreeStructure

        static boolean checkTreeStructure​(int numOfPartitions,
                                  int[] startOfSubTree)
        Checks for a valid subtree-structure. This code is taken from SMTinterpol.