Examples with Constraint com.sri.ai.grinder.api.Constraint used on opensource projects

Example 1 with Constraint

use of com.sri.ai.grinder.api.Constraint in project aic-expresso by aic-sri-international.

the class DefaultMultiVariableConstraint method conjoin.

@Override
public Constraint conjoin(Expression formula, Context context) {
    myAssert(() -> context.isLiteral(formula) || formula instanceof Constraint, () -> this.getClass() + " currently only supports conjoining with literals and constraints, but received " + formula);
    Constraint result;
    if (formula instanceof Constraint) {
        result = conjoinWithConjunctiveClause(formula, context);
    } else {
        result = conjoinWithLiteral(formula, context);
    }
    return result;
}

Example 2 with Constraint

use of com.sri.ai.grinder.api.Constraint in project aic-expresso by aic-sri-international.

the class AbstractSGVET method solve.

@Override
public Expression solve(MultiQuantifierEliminationProblem problem, Context context) {
    AssociativeCommutativeGroup group = problem.getGroup();
    List<Expression> indices = problem.getIndices();
    Expression indicesConstraint = problem.getConstraint();
    Expression body = problem.getBody();
    checkInterrupted();
    // Make sure body is simplified and quantifier-free.
    // context.getTheory().evaluate(body, context);
    Expression simplifiedBody = body;
    Expression result;
    if (getDebug()) {
        System.out.println("SGVE(T) input: " + simplifiedBody);
        System.out.println("Width        : " + width(simplifiedBody, context));
    }
    AssociativeCommutativeSemiRing semiRing = (AssociativeCommutativeSemiRing) group;
    Partition partition;
    if (indices.size() < 1) {
        partition = null;
    } else {
        Expression factoredConditionalsExpression = factoredConditionalsWithAbsorbingElseClause(semiRing, simplifiedBody, context);
        partition = pickPartition(semiRing, factoredConditionalsExpression, indices, context);
    }
    if (partition == null) {
        if (basicOutput) {
            System.out.println("No partition");
        }
        result = subSolver.solve(group, indices, indicesConstraint, simplifiedBody, context);
    } else {
        Expression indexSubProblemExpression = product(semiRing, partition.expressionsOnIndexAndNot.first, context);
        if (basicOutput) {
            System.out.println("Eliminating: " + getFirst(partition.index));
            System.out.println("From       : " + indexSubProblemExpression);
            System.out.println("Width      : " + width(indexSubProblemExpression, context) + " out of " + indices.size() + " indices");
        }
        // We now invoke the subsolver for summing the index out of the factors it is in.
        // Ideally, we would reuse the current constraint, but the set of index has changed and the current constraint may
        // use an internal representation that depends on its previous set of indices.
        // In the future, we should try to re-use that internal representation and re-index it appropriately, but for now
        // we rewrite the program in a way that the current constraint becomes a part of the input expression.
        // This will be equivalent to using it as a constraint, but will cause the constraint to be re-built.
        // BTW, the call to "project" below will also re-context the constraint for the same reason: re-indexing.
        // In the future it should also re-use the representation.
        // The following transformation is:  sum_C E   =   sum_{true} if C then E else 0
        Expression indexSubProblemExpressionWithConstraint = IfThenElse.make(indicesConstraint, indexSubProblemExpression, semiRing.multiplicativeAbsorbingElement());
        Expression indexSubProblemSolution = subSolver.extendContextAndSolve(group, partition.index, indexSubProblemExpressionWithConstraint, context);
        if (basicOutput) {
            System.out.println("Solution   : " + indexSubProblemSolution + "\n");
        }
        partition.expressionsOnIndexAndNot.second.add(indexSubProblemSolution);
        Expression remainingSubProblemExpression = product(semiRing, partition.expressionsOnIndexAndNot.second, context);
        // the constraint is already represented in indexSubProblemSolution
        Constraint constraintOnRemainingIndices = context;
        result = solve(group, partition.remainingIndices, constraintOnRemainingIndices, remainingSubProblemExpression, context);
        result = semiRing.multiply(result, context);
    }
    return result;
}

Example 3 with Constraint

use of com.sri.ai.grinder.api.Constraint in project aic-expresso by aic-sri-international.

the class CompoundTheoryWithDifferenceArithmeticTest method runCompleteSatisfiabilityTest.

/**
 * @param conjunction
 * @param expected
 */
private void runCompleteSatisfiabilityTest(String conjunction, Expression expected, Map<String, Type> variableNamesAndTypesForTesting) {
    TheoryTestingSupport equalityTheoryTestingSupport = TheoryTestingSupport.make(makeRandom(), new EqualityTheory(true, true));
    equalityTheoryTestingSupport.setVariableNamesAndTypesForTesting(variableNamesAndTypesForTesting);
    TheoryTestingSupport theoryTestingSupport = TheoryTestingSupport.make(makeRandom(), equalityTheoryTestingSupport, TheoryTestingSupport.make(makeRandom(), new PropositionalTheory()));
    Constraint context = theoryTestingSupport.makeContextWithTestingInformation();
    for (Expression literal : And.getConjuncts(parse(conjunction))) {
        context = context.conjoin(literal, theoryTestingSupport.makeContextWithTestingInformation());
    }
    assertEquals(expected, context);
}

Example 4 with Constraint

use of com.sri.ai.grinder.api.Constraint in project aic-expresso by aic-sri-international.

the class SGDPLLTTester method testCompleteMultiVariableConstraints.

/**
 * Given a theory and a number <code>n</code> of multi-variable constraint tests,
 * generates <code>n</code> formulas in the theory
 * and see if those detected as unsatisfiable by the corresponding solver
 * are indeed unsatisfiable (checked by brute force).
 * Throws an {@link Error} with the failure description if a test fails.
 * @param theoryTestingSupport
 * @param numberOfTests
 * @param maxNumberOfLiterals
 * @param outputCount
 */
public static void testCompleteMultiVariableConstraints(boolean testAgainstBruteForce, TheoryTestingSupport theoryTestingSupport, long numberOfTests, int maxNumberOfLiterals, boolean outputCount) {
    Context context = theoryTestingSupport.makeContextWithTestingInformation();
    NullaryFunction<Constraint> makeInitialConstraint = () -> context;
    Function<Constraint, Expression> makeRandomLiteral = c -> theoryTestingSupport.makeRandomLiteral(context);
    // CompleteMultiVariableContext is complete
    TestRunner tester = SGDPLLTTester::testCompleteSatisfiability;
    runTesterGivenOnSuccessiveConjunctionsOfLiterals("complete satisfiability", tester, numberOfTests, maxNumberOfLiterals, testAgainstBruteForce, theoryTestingSupport, makeInitialConstraint, makeRandomLiteral, outputCount, context);
}

Example 5 with Constraint

use of com.sri.ai.grinder.api.Constraint in project aic-expresso by aic-sri-international.

the class SGDPLLTTester method runModelCountingTestForSingleVariableConstraint.

private static void runModelCountingTestForSingleVariableConstraint(Expression variable, Collection<Expression> literals, Constraint constraint, boolean testAgainstBruteForce, Theory theory, Context context) {
    Expression literalsConjunction = And.make(literals);
    String problemDescription = "model counting of " + literalsConjunction + " for variable " + variable;
    output("Problem: " + problemDescription);
    Simplifier symbolicSolver = (e, p) -> computeModelCountBySolver((SingleVariableConstraint) e, p);
    SingleVariableConstraint singleVariableConstraint = (SingleVariableConstraint) constraint;
    Expression symbolicSolution = symbolicSolver.apply(singleVariableConstraint, context);
    if (Util.thereExists(new SubExpressionsDepthFirstIterator(symbolicSolution), e -> e instanceof QuantifiedExpression || Sets.isIntensionalSet(e))) {
        throw new Error("Symbolic solution is not quantifier-free: " + symbolicSolution);
    }
    output("Symbolic result: " + symbolicSolution);
    if (testAgainstBruteForce) {
        if (singleVariableConstraint.isContradiction()) {
            if (!symbolicSolution.equals(ZERO)) {
                throw new Error("Constraint is contradiction, but symbolic solver does not produce 0, but instead " + symbolicSolution);
            }
        } else {
            Expression testingVariable = singleVariableConstraint.getVariable();
            Set<Expression> allVariables = getVariablesBeingReferenced(singleVariableConstraint, context);
            Collection<? extends Expression> otherVariables = removeFromSetNonDestructively(allVariables, v -> v.equals(testingVariable));
            BinaryFunction<BruteForceCommonInterpreter, Context, Expression> fromInterpreterAndContextWithAssignmentToOtherVariablesToBruteForceSolution = (interpreter, contextWithAssignmentToOtherVariables) -> bruteForceModelCounterForVariableGivenInterpreterAndAssignmentToOtherVariables(variable, literalsConjunction, interpreter, theory, contextWithAssignmentToOtherVariables);
            testSymbolicVsBruteForceComputationForEachAssignment(theory, problemDescription, otherVariables, symbolicSolution, fromInterpreterAndContextWithAssignmentToOtherVariablesToBruteForceSolution, context);
        }
    } else {
        output("Skipping test againt brute-force.");
    }
}