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

Example 16 with Literal

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

the class EncodingResult method addClause.

/**
 * Adds a clause to the result
 * @param literals the literals of the clause
 */
public void addClause(final Literal... literals) {
    if (this.miniSat == null) {
        this.result.add(this.f.clause(literals));
    } else {
        final LNGIntVector clauseVec = new LNGIntVector(literals.length);
        for (final Literal literal : literals) {
            addLiteral(clauseVec, literal);
        }
        this.miniSat.underlyingSolver().addClause(clauseVec, this.proposition);
        this.miniSat.setSolverToUndef();
    }
}

Example 17 with Literal

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

the class CCAMONested method encodeIntern.

/**
 * Internal recursive encoding.
 * @param vars the variables of the constraint
 */
private void encodeIntern(final LNGVector<Literal> vars) {
    if (vars.size() <= this.groupSize) {
        for (int i = 0; i + 1 < vars.size(); i++) {
            for (int j = i + 1; j < vars.size(); j++) {
                this.result.addClause(vars.get(i).negate(), vars.get(j).negate());
            }
        }
    } else {
        final LNGVector<Literal> l1 = new LNGVector<>(vars.size() / 2);
        final LNGVector<Literal> l2 = new LNGVector<>(vars.size() / 2);
        int i = 0;
        for (; i < vars.size() / 2; i++) {
            l1.push(vars.get(i));
        }
        for (; i < vars.size(); i++) {
            l2.push(vars.get(i));
        }
        final Variable newVariable = this.result.newVariable();
        l1.push(newVariable);
        l2.push(newVariable.negate());
        this.encodeIntern(l1);
        this.encodeIntern(l2);
    }
}

Example 18 with Literal

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

the class DnnfCompiler method cnf2Ddnnf.

protected Formula cnf2Ddnnf(final DTree tree, final int currentShannons) throws TimeoutException {
    final BitSet separator = tree.dynamicSeparator();
    final Formula implied = this.newlyImpliedLiterals(tree.staticVarSet());
    if (separator.isEmpty()) {
        if (tree instanceof DTreeLeaf) {
            return this.f.and(implied, leaf2Ddnnf((DTreeLeaf) tree));
        } else {
            return conjoin(implied, (DTreeNode) tree, currentShannons);
        }
    } else {
        final int var = chooseShannonVariable(tree, separator, currentShannons);
        if (this.handler != null && !this.handler.shannonExpansion()) {
            throw new TimeoutException();
        }
        /* Positive branch */
        Formula positiveDnnf = this.f.falsum();
        if (this.solver.decide(var, true)) {
            positiveDnnf = cnf2Ddnnf(tree, currentShannons + 1);
        }
        this.solver.undoDecide(var);
        if (positiveDnnf == this.f.falsum()) {
            if (this.solver.atAssertionLevel() && this.solver.assertCdLiteral()) {
                return cnf2Ddnnf(tree);
            } else {
                return this.f.falsum();
            }
        }
        /* Negative branch */
        Formula negativeDnnf = this.f.falsum();
        if (this.solver.decide(var, false)) {
            negativeDnnf = cnf2Ddnnf(tree, currentShannons + 1);
        }
        this.solver.undoDecide(var);
        if (negativeDnnf == this.f.falsum()) {
            if (this.solver.atAssertionLevel() && this.solver.assertCdLiteral()) {
                return cnf2Ddnnf(tree);
            } else {
                return this.f.falsum();
            }
        }
        final Literal lit = this.solver.litForIdx(var);
        final Formula positiveBranch = this.f.and(lit, positiveDnnf);
        final Formula negativeBranch = this.f.and(lit.negate(), negativeDnnf);
        return this.f.and(implied, this.f.or(positiveBranch, negativeBranch));
    }
}

Example 19 with Literal

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

the class DnnfCompiler method leaf2Ddnnf.

protected Formula leaf2Ddnnf(final DTreeLeaf leaf) {
    final Iterator<Literal> literals = leaf.clause().literals().iterator();
    this.leafResultOperands.clear();
    this.leafCurrentLiterals.clear();
    Literal lit;
    int index = 0;
    while (literals.hasNext()) {
        lit = literals.next();
        switch(this.solver.valueOf(MiniSatStyleSolver.mkLit(this.solver.variableIndex(lit), !lit.phase()))) {
            case TRUE:
                return this.f.verum();
            case UNDEF:
                this.leafCurrentLiterals.add(lit);
                this.leafResultOperands.add(this.f.and(this.leafCurrentLiterals));
                this.leafCurrentLiterals.set(index, lit.negate());
                index++;
        }
    }
    return this.f.or(this.leafResultOperands);
}

Example 20 with Literal

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

the class DnnfMiniSatStyleSolver method generateClauseVector.

protected LNGIntVector generateClauseVector(final Collection<Literal> literals) {
    final LNGIntVector clauseVec = new LNGIntVector(literals.size());
    for (final Literal lit : literals) {
        int index = idxForName(lit.name());
        if (index == -1) {
            index = newVar(false, true);
            addName(lit.name(), index);
        }
        final int litNum = lit.phase() ? index * 2 : (index * 2) ^ 1;
        clauseVec.push(litNum);
    }
    return clauseVec;
}