Examples with IntegerFormula org.sosy_lab.java_smt.api.NumeralFormula.IntegerFormula used on opensource projects

Example 1 with IntegerFormula

use of org.sosy_lab.java_smt.api.NumeralFormula.IntegerFormula in project java-smt by sosy-lab.

the class Interpolation method interpolateProgramTrace.

/**
 * Example for encoding a program path and computing interpolants along the path. Taken from <a
 * href="http://satsmt2014.forsyte.at/files/2014/01/interpolation_philipp.pdf">slides</a> from
 * Philipp Rümmer.
 *
 * <p>Example trace of a program:
 *
 * <pre>
 * i=0
 * k=j
 * assume (i<50)
 * i++
 * k++
 * assume (i>=50)
 * assume (j==0)
 * assume (k<50)
 * </pre>
 */
private static <T> void interpolateProgramTrace(InterpolatingProverEnvironment<T> prover, IntegerFormulaManager imgr, LogManager logger) throws InterruptedException, SolverException {
    // create some variables.
    // primed variable needed for 'self-assignments', alternatively use SSA-indices.
    IntegerFormula i = imgr.makeVariable("i");
    IntegerFormula i1 = imgr.makeVariable("i'");
    IntegerFormula j = imgr.makeVariable("j");
    IntegerFormula k = imgr.makeVariable("k");
    IntegerFormula k1 = imgr.makeVariable("k'");
    IntegerFormula zero = imgr.makeNumber(0);
    IntegerFormula one = imgr.makeNumber(1);
    IntegerFormula fifty = imgr.makeNumber(50);
    // create and assert some formulas.
    List<BooleanFormula> programTrace = ImmutableList.of(imgr.equal(i, zero), imgr.equal(k, j), imgr.lessThan(i, fifty), imgr.equal(i1, imgr.add(i, one)), imgr.equal(k1, imgr.add(k, one)), imgr.greaterOrEquals(i1, fifty), imgr.equal(j, zero), imgr.lessThan(k1, fifty));
    // assert all formulas in the prover
    List<T> handles = new ArrayList<>();
    for (BooleanFormula step : programTrace) {
        handles.add(prover.addConstraint(step));
    }
    // check for satisfiability
    boolean unsat = prover.isUnsat();
    Preconditions.checkState(unsat, "the example for interpolation should be UNSAT");
    // get a sequence of interpolants for the program trace.
    List<BooleanFormula> itps = prover.getSeqInterpolants0(handles);
    logger.log(Level.INFO, "Interpolants for the program trace are:", itps);
}

Example 2 with IntegerFormula

use of org.sosy_lab.java_smt.api.NumeralFormula.IntegerFormula in project java-smt by sosy-lab.

the class OptimizationFormulaWeights method optimizeWithWeights.

/**
 * add some constraints and then solve them with optimization according to weights.
 */
private static void optimizeWithWeights(OptimizationProverEnvironment prover, BooleanFormulaManager bmgr, IntegerFormulaManager imgr, LogManager logger) throws InterruptedException, SolverException {
    // create some symbols and formulas
    IntegerFormula x = imgr.makeVariable("x");
    IntegerFormula y = imgr.makeVariable("y");
    IntegerFormula z = imgr.makeVariable("z");
    IntegerFormula zero = imgr.makeNumber(0);
    IntegerFormula four = imgr.makeNumber(4);
    IntegerFormula ten = imgr.makeNumber(10);
    IntegerFormula scoreBasic = imgr.makeNumber(0);
    IntegerFormula scoreLow = imgr.makeNumber(2);
    IntegerFormula scoreMedium = imgr.makeNumber(4);
    IntegerFormula scoreHigh = imgr.makeNumber(10);
    // add some very important constraints: x<10, y<10, z<10, 10=x+y+z
    prover.addConstraint(bmgr.and(// very important -> direct constraint
    imgr.lessOrEquals(x, ten), // very important -> direct constraint
    imgr.lessOrEquals(y, ten), // very important -> direct constraint
    imgr.lessOrEquals(z, ten), imgr.equal(ten, imgr.add(x, imgr.add(y, z)))));
    // generate weighted formulas: if a formula should be satisfied,
    // use higher weight for the positive instance than for its negated instance.
    List<IntegerFormula> weights = ImmutableList.of(// important
    bmgr.ifThenElse(imgr.lessOrEquals(x, zero), scoreHigh, scoreBasic), // important
    bmgr.ifThenElse(imgr.lessOrEquals(x, four), scoreHigh, scoreBasic), // less important
    bmgr.ifThenElse(imgr.lessOrEquals(y, zero), scoreMedium, scoreBasic), // less important
    bmgr.ifThenElse(imgr.lessOrEquals(y, four), scoreMedium, scoreBasic), // not important
    bmgr.ifThenElse(imgr.lessOrEquals(z, zero), scoreLow, scoreBasic), // important
    bmgr.ifThenElse(imgr.lessOrEquals(z, four), scoreHigh, scoreBasic));
    // Maximize sum of weights
    int handle = prover.maximize(imgr.sum(weights));
    OptStatus response = prover.check();
    assert response == OptStatus.OPT;
    // ideal solution: sum=32 with e.g. x=0,y=6,z=4  or  x=0,y=7,z=3  or  x=0,y=8,z=2 ...
    try (Model model = prover.getModel()) {
        logger.log(Level.INFO, "maximal sum ", prover.upper(handle, Rational.ZERO).orElseThrow(), "with model", model.asList());
    }
}

Example 3 with IntegerFormula

use of org.sosy_lab.java_smt.api.NumeralFormula.IntegerFormula in project java-smt by sosy-lab.

the class OptimizationIntReal method optimizeWithIntegers.

/**
 * Solve the problem with integer logic.
 */
private static void optimizeWithIntegers(Configuration config, LogManager logger, ShutdownNotifier notifier, Solvers solver) throws InterruptedException, SolverException {
    // create solver context
    try (SolverContext context = SolverContextFactory.createSolverContext(config, logger, notifier, solver);
        OptimizationProverEnvironment prover = context.newOptimizationProverEnvironment(ProverOptions.GENERATE_MODELS)) {
        logger.log(Level.WARNING, "Using solver " + solver + " in version " + context.getVersion());
        BooleanFormulaManager bmgr = context.getFormulaManager().getBooleanFormulaManager();
        IntegerFormulaManager nmgr = context.getFormulaManager().getIntegerFormulaManager();
        IntegerFormula x = nmgr.makeVariable("x");
        // assert  0 <= x < 10
        prover.addConstraint(bmgr.and(nmgr.greaterOrEquals(x, nmgr.makeNumber(0)), nmgr.lessThan(x, nmgr.makeNumber(10))));
        logger.log(Level.INFO, "optimizing with integer logic");
        printUpperAndLowerBound(prover, x, logger);
    } catch (InvalidConfigurationException | UnsatisfiedLinkError e) {
        // on some machines we support only some solvers,
        // thus we can ignore these errors.
        logger.logUserException(Level.INFO, e, "Solver " + solver + " is not available.");
    } catch (UnsupportedOperationException e) {
        logger.logUserException(Level.INFO, e, e.getMessage());
    }
}

Example 4 with IntegerFormula

use of org.sosy_lab.java_smt.api.NumeralFormula.IntegerFormula in project java-smt by sosy-lab.

the class AllSatExample method allSatIntegers.

/**
 * For integer formulas, we can implement the allsat-loop and collect all models when iterating.
 */
private List<List<ValueAssignment>> allSatIntegers() throws InterruptedException, SolverException {
    bfmgr = context.getFormulaManager().getBooleanFormulaManager();
    ifmgr = context.getFormulaManager().getIntegerFormulaManager();
    // formula ((1 <= a <= 10) && (1 <= b <= 10) && (a >= 2 * b)) with 25 models
    IntegerFormula a = ifmgr.makeVariable("a");
    IntegerFormula b = ifmgr.makeVariable("b");
    prover.addConstraint(ifmgr.lessOrEquals(num(1), a));
    prover.addConstraint(ifmgr.lessOrEquals(a, num(10)));
    prover.addConstraint(ifmgr.lessOrEquals(num(1), b));
    prover.addConstraint(ifmgr.lessOrEquals(b, num(10)));
    prover.addConstraint(ifmgr.greaterOrEquals(a, ifmgr.multiply(num(2), b)));
    List<List<ValueAssignment>> models = new ArrayList<>();
    // loop over all possible models for "1<=a<=10 AND 1<=b<=10 AND a==2*b"
    while (!prover.isUnsat()) {
        models.add(prover.getModelAssignments());
        try (Model model = prover.getModel()) {
            // convert model into formula, assuming we know all symbols and know they are integers
            BooleanFormula modelAsFormula = bfmgr.and(ifmgr.equal(a, num(model.evaluate(a))), ifmgr.equal(b, num(model.evaluate(b))));
            // prevent next model from using the same assignment as a previous model
            prover.addConstraint(bfmgr.not(modelAsFormula));
        }
    }
    return models;
}

Example 5 with IntegerFormula

use of org.sosy_lab.java_smt.api.NumeralFormula.IntegerFormula in project java-smt by sosy-lab.

the class AllSatExample method allSatIntegers2.

/**
 * For integer formulas, we can implement the allsat-loop and collect all models when iterating.
 */
private List<List<ValueAssignment>> allSatIntegers2() throws InterruptedException, SolverException {
    bfmgr = context.getFormulaManager().getBooleanFormulaManager();
    ifmgr = context.getFormulaManager().getIntegerFormulaManager();
    // formula ((1 <= a <= 3) && (0 == b) && (p == q)) with 6 models
    IntegerFormula a = ifmgr.makeVariable("a");
    IntegerFormula b = ifmgr.makeVariable("b");
    BooleanFormula p = bfmgr.makeVariable("p");
    BooleanFormula q = bfmgr.makeVariable("q");
    prover.addConstraint(ifmgr.lessOrEquals(num(1), a));
    prover.addConstraint(ifmgr.equal(num(0), b));
    prover.addConstraint(ifmgr.lessOrEquals(a, num(3)));
    prover.addConstraint(bfmgr.equivalence(p, q));
    List<List<ValueAssignment>> models = new ArrayList<>();
    // loop over all possible models for "1<=a<=3 AND p=q"
    while (!prover.isUnsat()) {
        final ImmutableList<ValueAssignment> modelAssignments = prover.getModelAssignments();
        models.add(modelAssignments);
        final List<BooleanFormula> modelAssignmentsAsFormulas = new ArrayList<>();
        for (ValueAssignment va : modelAssignments) {
            modelAssignmentsAsFormulas.add(va.getAssignmentAsFormula());
        }
        // prevent next model from using the same assignment as a previous model
        prover.addConstraint(bfmgr.not(bfmgr.and(modelAssignmentsAsFormulas)));
    }
    return models;
}