org.sosy_lab.java_smt.api

Interface InterpolatingProverEnvironment<T>

Type Parameters:

T - The type of the objects which can be used to select formulas for interpolant creation.

All Superinterfaces:

AutoCloseable, BasicProverEnvironment<T>

All Known Implementing Classes:

InterpolatingProverWithAssumptionsWrapper, ReusableStackInterpolatingProver

public interface InterpolatingProverEnvironment<T>
extends BasicProverEnvironment<T>

This class provides an interface to an incremental SMT solver with methods for pushing and popping formulas as well as SAT checks. Furthermore, interpolants can be generated for an unsatisfiable list of formulas.

See Also:

The non-interpolating ProverEnvironment for general notes that also apply to this interface.

Nested Class Summary

Nested classes/interfaces inherited from interface org.sosy_lab.java_smt.api.BasicProverEnvironment

BasicProverEnvironment.AllSatCallback<R>

Field Summary

Fields inherited from interface org.sosy_lab.java_smt.api.BasicProverEnvironment

NO_MODEL_HELP

Method Summary

Modifier and Type	Method and Description
static boolean	checkTreeStructure(int numOfPartitions, int[] startOfSubTree) Checks for a valid subtree-structure.
BooleanFormula	getInterpolant(Collection<T> formulasOfA) Get an interpolant for two groups of formulas.
default List<BooleanFormula>	getSeqInterpolants(List<? extends Collection<T>> partitionedFormulas) This method returns interpolants of an 'inductive sequence'.
default List<BooleanFormula>	getSeqInterpolants0(List<T> formulas)
List<BooleanFormula>	getTreeInterpolants(List<? extends Collection<T>> partitionedFormulas, int[] startOfSubTree) Compute a sequence of interpolants.
default List<BooleanFormula>	getTreeInterpolants0(List<T> formulas, int[] startOfSubTree)

Methods inherited from interface org.sosy_lab.java_smt.api.BasicProverEnvironment

addConstraint, allSat, close, getModel, getModelAssignments, getUnsatCore, isUnsat, isUnsatWithAssumptions, pop, push, push, unsatCoreOverAssumptions

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

getSeqInterpolants0

default List<BooleanFormula> getSeqInterpolants0(List<T> formulas)
                                          throws SolverException,
                                                 InterruptedException

Throws:

SolverException

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

getTreeInterpolants0

default List<BooleanFormula> getTreeInterpolants0(List<T> formulas,
                                                  int[] startOfSubTree)
                                           throws SolverException,
                                                  InterruptedException

Throws:

SolverException

InterruptedException

checkTreeStructure

static boolean checkTreeStructure(int numOfPartitions,
                                  int[] startOfSubTree)

Checks for a valid subtree-structure. This code is taken from SMTinterpol.