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

Example 1 with BinaryOperator

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

the class FormulaStringRepresentation method toInnerString.

/**
 * Returns the string representation of the given formula.
 * <p>
 * This method is used for recursive calls in order to format the sub-formulas.
 * @param formula the formula
 * @return the string representation of the formula
 */
protected String toInnerString(final Formula formula) {
    switch(formula.type()) {
        case FALSE:
            return this.falsum();
        case TRUE:
            return this.verum();
        case LITERAL:
            final Literal lit = (Literal) formula;
            return lit.phase() ? lit.name() : this.negation() + lit.name();
        case NOT:
            final Not not = (Not) formula;
            return this.negation() + this.bracket(not.operand());
        case IMPL:
        case EQUIV:
            final BinaryOperator binary = (BinaryOperator) formula;
            String op = formula.type() == FType.IMPL ? this.implication() : this.equivalence();
            return this.binaryOperator(binary, op);
        case AND:
        case OR:
            final NAryOperator nary = (NAryOperator) formula;
            op = formula.type() == FType.AND ? this.and() : this.or();
            return this.naryOperator(nary, String.format("%s", op));
        case PBC:
            final PBConstraint pbc = (PBConstraint) formula;
            return String.format("%s%s%d", this.pbLhs(pbc.operands(), pbc.coefficients()), this.pbComparator(pbc.comparator()), pbc.rhs());
        default:
            throw new IllegalArgumentException("Cannot print the unknown formula type " + formula.type());
    }
}

Example 2 with BinaryOperator

use of org.logicng.formulas.BinaryOperator 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 3 with BinaryOperator

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

the class DFSOrdering method dfs.

private void dfs(final Formula formula, final LinkedHashSet<Variable> variables) {
    switch(formula.type()) {
        case LITERAL:
            variables.add(((Literal) formula).variable());
            break;
        case NOT:
            dfs(((Not) formula).operand(), variables);
            break;
        case IMPL:
        case EQUIV:
            final BinaryOperator op = (BinaryOperator) formula;
            dfs(op.left(), variables);
            dfs(op.right(), variables);
            break;
        case AND:
        case OR:
            for (final Formula o : formula) {
                dfs(o, variables);
            }
            break;
        case PBC:
            final PBConstraint pbc = (PBConstraint) formula;
            for (final Literal lit : pbc.operands()) {
                variables.add(lit.variable());
            }
            break;
    }
}

Example 4 with BinaryOperator

use of org.logicng.formulas.BinaryOperator 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 5 with BinaryOperator

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

the class LiteralSubstitution method apply.

@Override
public Formula apply(final Formula formula, final boolean cache) {
    final FormulaFactory f = formula.factory();
    switch(formula.type()) {
        case TRUE:
        case FALSE:
            return formula;
        case LITERAL:
            final Literal literal = (Literal) formula;
            Literal lit = this.substitution.get(literal);
            if (lit != null) {
                return lit;
            }
            if (!literal.phase()) {
                lit = this.substitution.get(literal.variable());
                return lit != null ? lit.negate() : formula;
            }
            return formula;
        case NOT:
            return f.not(apply(((Not) formula).operand(), cache));
        case EQUIV:
        case IMPL:
            final BinaryOperator binOp = (BinaryOperator) formula;
            return f.binaryOperator(formula.type(), apply(binOp.left(), cache), apply(binOp.right(), cache));
        case OR:
        case AND:
            final List<Formula> operands = new ArrayList<>();
            for (final Formula op : formula) {
                operands.add(apply(op, cache));
            }
            return f.naryOperator(formula.type(), operands);
        case PBC:
            final PBConstraint pbc = (PBConstraint) formula;
            final Literal[] originalOperands = pbc.operands();
            final Literal[] literals = new Literal[originalOperands.length];
            for (int i = 0; i < literals.length; i++) {
                literals[i] = (Literal) apply(originalOperands[i], false);
            }
            return f.pbc(pbc.comparator(), pbc.rhs(), literals, pbc.coefficients());
        default:
            throw new IllegalArgumentException("Unknown formula type: " + formula.type());
    }
}