Examples with PBConstraint org.logicng.formulas.PBConstraint used on opensource projects

Example 6 with PBConstraint

use of org.logicng.formulas.PBConstraint in project LogicNG by logic-ng.

the class PureExpansionTransformation method apply.

@Override
public Formula apply(final Formula formula, final boolean cache) {
    final FormulaFactory f = formula.factory();
    switch(formula.type()) {
        case FALSE:
        case TRUE:
        case LITERAL:
            return formula;
        case NOT:
            final Not not = (Not) formula;
            return f.not(apply(not.operand(), cache));
        case OR:
        case AND:
            final NAryOperator nary = (NAryOperator) formula;
            final List<Formula> newOps = new ArrayList<>(nary.numberOfOperands());
            for (final Formula op : nary) {
                newOps.add(apply(op, cache));
            }
            return f.naryOperator(formula.type(), newOps);
        case IMPL:
        case EQUIV:
            final BinaryOperator binary = (BinaryOperator) formula;
            final Formula newLeft = apply(binary.left(), cache);
            final Formula newRight = apply(binary.right(), cache);
            return f.binaryOperator(formula.type(), newLeft, newRight);
        case PBC:
            final PBConstraint pbc = (PBConstraint) formula;
            if (pbc.isAmo() || pbc.isExo()) {
                final EncodingResult encodingResult = EncodingResult.resultForFormula(f);
                final Variable[] vars = literalsAsVariables(pbc.operands());
                this.amoEncoder.build(encodingResult, vars);
                final List<Formula> encoding = encodingResult.result();
                if (pbc.isExo()) {
                    encoding.add(f.or(vars));
                }
                return f.and(encoding);
            } else {
                throw new UnsupportedOperationException("Pure encoding for a PBC of type other than AMO or EXO is currently not supported.");
            }
        default:
            throw new IllegalStateException("Unknown formula type: " + formula.type());
    }
}

Example 7 with PBConstraint

use of org.logicng.formulas.PBConstraint in project LogicNG by logic-ng.

the class MiniSat method add.

@Override
public void add(final Formula formula, final Proposition proposition) {
    this.result = UNDEF;
    if (formula.type() == FType.PBC) {
        final PBConstraint constraint = (PBConstraint) formula;
        if (constraint.isCC()) {
            if (this.style == SolverStyle.MINICARD) {
                if (constraint.comparator() == CType.LE) {
                    ((MiniCard) this.solver).addAtMost(generateClauseVector(Arrays.asList(constraint.operands())), constraint.rhs());
                } else if (constraint.comparator() == CType.LT && constraint.rhs() > 3) {
                    ((MiniCard) this.solver).addAtMost(generateClauseVector(Arrays.asList(constraint.operands())), constraint.rhs() - 1);
                } else if (constraint.comparator() == CType.EQ && constraint.rhs() == 1) {
                    ((MiniCard) this.solver).addAtMost(generateClauseVector(Arrays.asList(constraint.operands())), constraint.rhs());
                    this.solver.addClause(generateClauseVector(Arrays.asList(constraint.operands())), proposition);
                } else {
                    addFormulaAsCNF(constraint, proposition);
                }
            } else {
                final EncodingResult result = EncodingResult.resultForMiniSat(this.f, this, proposition);
                this.ccEncoder.encode((CardinalityConstraint) constraint, result);
            }
        } else {
            addFormulaAsCNF(constraint, proposition);
        }
    } else {
        addFormulaAsCNF(formula, proposition);
    }
}

Example 8 with PBConstraint

use of org.logicng.formulas.PBConstraint in project LogicNG by logic-ng.

the class ConnectedComponentsComputerTest method testFormulaSplit.

@Test
public void testFormulaSplit() throws IOException, ParserException {
    final FormulaFactory f = new FormulaFactory();
    f.putConfiguration(CCConfig.builder().amoEncoding(CCConfig.AMO_ENCODER.PURE).build());
    final Formula parsed = FormulaReader.readPseudoBooleanFormula("src/test/resources/formulas/formula1.txt", f);
    final List<Formula> formulas = new ArrayList<>();
    final List<Formula> originalFormulas = new ArrayList<>();
    for (final Formula formula : parsed) {
        originalFormulas.add(formula);
        if (formula instanceof PBConstraint) {
            formulas.add(formula);
        } else {
            formulas.add(formula.transform(new CNFFactorization()));
        }
    }
    final Graph<Variable> constraintGraph = ConstraintGraphGenerator.generateFromCnf(formulas);
    final Set<Set<Node<Variable>>> ccs = ConnectedComponentsComputation.compute(constraintGraph);
    final List<List<Formula>> split = ConnectedComponentsComputation.splitFormulasByComponent(originalFormulas, ccs);
    assertThat(split).hasSize(4);
    assertThat(split.get(0)).hasSize(1899);
    assertThat(split.get(1)).hasSize(3);
    assertThat(split.get(2)).hasSize(3);
    assertThat(split.get(3)).hasSize(3);
}

Example 9 with PBConstraint

use of org.logicng.formulas.PBConstraint in project LogicNG by logic-ng.

the class PBEncoderTest method testCC0.

@Test
public void testCC0() {
    for (final PBEncoder encoder : this.encoders) {
        final int numLits = 100;
        final List<Literal> lits = new ArrayList<>();
        final List<Integer> coeffs = new ArrayList<>();
        final Variable[] problemLits = new Variable[numLits];
        for (int i = 0; i < numLits; i++) {
            final Variable var = this.f.variable("v" + i);
            lits.add(var);
            problemLits[i] = var;
            coeffs.add(1);
        }
        final List<Formula> clauses = encoder.encode((PBConstraint) this.f.pbc(CType.LE, 0, lits, coeffs));
        final SATSolver solver = MiniSat.miniSat(this.f);
        solver.add(clauses);
        assertSolverSat(solver);
        assertThat(solver.enumerateAllModels(problemLits)).hasSize(1).allMatch(m -> m.positiveVariables().isEmpty());
    }
}

Example 10 with PBConstraint

use of org.logicng.formulas.PBConstraint in project LogicNG by logic-ng.

the class PBEncoderTest method testCCNormalized.

@Test
public void testCCNormalized() throws ParserException {
    final List<Literal> lits = new ArrayList<>();
    lits.add(this.f.literal("m", true));
    lits.add(this.f.literal("n", true));
    final List<Integer> coeffs2 = new ArrayList<>();
    coeffs2.add(2);
    coeffs2.add(2);
    final PBConstraint normCC = (PBConstraint) this.f.pbc(CType.LE, 2, lits, coeffs2);
    assertThat(this.encoders[0].encode(normCC)).containsExactly(this.f.parse("~m | ~n"));
}