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

Example 6 with Literal

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

the class LiteralProfileFunction method nonCachingRecursion.

/**
 * Recursive function for the non-caching literal profile computation.
 * @param formula the formula
 * @param map     the literal profile
 */
private static void nonCachingRecursion(final Formula formula, final Map<Literal, Integer> map) {
    if (formula.type() == FType.LITERAL) {
        final Literal lit = (Literal) formula;
        map.merge(lit, 1, Integer::sum);
    } else if (formula.type() == FType.PBC) {
        for (final Literal l : formula.literals()) {
            nonCachingRecursion(l, map);
        }
    } else {
        for (final Formula op : formula) {
            nonCachingRecursion(op, map);
        }
    }
}

Example 7 with Literal

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

the class MinimumPrimeImplicantFunction method apply.

@Override
public SortedSet<Literal> apply(final Formula formula, final boolean cache) {
    final Formula nnf = formula.nnf();
    final Map<Variable, Literal> newVar2oldLit = new HashMap<>();
    final LiteralSubstitution substitution = new LiteralSubstitution();
    for (final Literal literal : nnf.literals()) {
        final Variable newVar = formula.factory().variable(literal.name() + (literal.phase() ? POS : NEG));
        newVar2oldLit.put(newVar, literal);
        substitution.addSubstitution(literal, newVar);
    }
    final Formula substitued = nnf.transform(substitution);
    final SATSolver solver = MiniSat.miniSat(formula.factory(), MiniSatConfig.builder().cnfMethod(MiniSatConfig.CNFMethod.PG_ON_SOLVER).build());
    solver.add(substitued);
    for (final Literal literal : newVar2oldLit.values()) {
        if (literal.phase() && newVar2oldLit.containsValue(literal.negate())) {
            solver.add(formula.factory().amo(formula.factory().variable(literal.name() + POS), formula.factory().variable(literal.name() + NEG)));
        }
    }
    if (solver.sat() != Tristate.TRUE) {
        return null;
    }
    final Assignment minimumModel = solver.execute(OptimizationFunction.minimize(newVar2oldLit.keySet()));
    final SortedSet<Literal> primeImplicant = new TreeSet<>();
    for (final Variable variable : minimumModel.positiveVariables()) {
        final Literal literal = newVar2oldLit.get(variable);
        if (literal != null) {
            primeImplicant.add(literal);
        }
    }
    return primeImplicant;
}

Example 8 with Literal

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

the class VariableProfileFunction method nonCachingRecursion.

/**
 * Recursive function for the non-caching variable profile computation.
 * @param formula the formula
 * @param map     the variable profile
 */
private static void nonCachingRecursion(final Formula formula, final Map<Variable, Integer> map) {
    if (formula.type() == FType.LITERAL) {
        final Literal lit = (Literal) formula;
        map.merge(lit.variable(), 1, Integer::sum);
    } else if (formula.type() == FType.PBC) {
        for (final Literal l : formula.literals()) {
            nonCachingRecursion(l.variable(), map);
        }
    } else {
        for (final Formula op : formula) {
            nonCachingRecursion(op, map);
        }
    }
}

Example 9 with Literal

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

the class VariablesFunction method apply.

@Override
public SortedSet<Variable> apply(final Formula formula, final boolean cache) {
    final Object cached = formula.functionCacheEntry(VARIABLES);
    if (cached != null) {
        return (SortedSet<Variable>) cached;
    }
    SortedSet<Variable> result = new TreeSet<>();
    switch(formula.type()) {
        case FALSE:
        case TRUE:
            result = new TreeSet<>();
            break;
        case LITERAL:
            final Literal lit = (Literal) formula;
            result.add(lit.variable());
            break;
        case NOT:
            final Not not = (Not) formula;
            result = apply(not.operand(), cache);
            break;
        case IMPL:
        case EQUIV:
            final BinaryOperator binary = (BinaryOperator) formula;
            result.addAll(apply(binary.left(), cache));
            result.addAll(apply(binary.right(), cache));
            break;
        case OR:
        case AND:
            final NAryOperator nary = (NAryOperator) formula;
            for (final Formula op : nary) {
                result.addAll(apply(op, cache));
            }
            break;
        case PBC:
            final PBConstraint pbc = (PBConstraint) formula;
            result = FormulaHelper.variables(pbc.literals());
            break;
        default:
            throw new IllegalStateException("Unknown formula type " + formula.type());
    }
    result = Collections.unmodifiableSortedSet(result);
    if (cache) {
        formula.setFunctionCacheEntry(VARIABLES, result);
    }
    return result;
}

Example 10 with Literal

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

the class CCCardinalityNetworks method buildALK.

void buildALK(final EncodingResult result, final Variable[] vars, final int rhs) {
    result.reset();
    final LNGVector<Literal> input = new LNGVector<>();
    final LNGVector<Literal> output = new LNGVector<>();
    final int newRHS = vars.length - rhs;
    if (newRHS > vars.length / 2) {
        final int geq = vars.length - newRHS;
        for (final Variable v : vars) {
            input.push(v);
        }
        this.sorting.sort(geq, input, result, output, OUTPUT_TO_INPUT);
        for (int i = 0; i < geq; i++) {
            result.addClause(output.get(i));
        }
    } else {
        for (final Variable v : vars) {
            input.push(v.negate());
        }
        this.sorting.sort(newRHS + 1, input, result, output, INPUT_TO_OUTPUT);
        assert output.size() > newRHS;
        result.addClause(output.get(newRHS).negate());
    }
}