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

Example 21 with Formula

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

the class DNFPredicate method test.

@Override
public boolean test(final Formula formula, final boolean cache) {
    final Tristate cached = formula.predicateCacheEntry(IS_DNF);
    if (cached != Tristate.UNDEF) {
        return cached == Tristate.TRUE;
    }
    boolean result;
    switch(formula.type()) {
        case FALSE:
        case TRUE:
        case LITERAL:
            return true;
        case NOT:
        case IMPL:
        case EQUIV:
        case PBC:
            return false;
        case OR:
            result = true;
            for (final Formula op : formula) {
                if (!getMaxtermPredicate().test(op, false)) {
                    result = false;
                }
            }
            break;
        case AND:
            result = getMaxtermPredicate().test(formula, false);
            break;
        default:
            throw new IllegalArgumentException("Cannot compute DNF predicate on " + formula.type());
    }
    if (cache) {
        formula.setPredicateCacheEntry(IS_DNF, result);
    }
    return result;
}

Example 22 with Formula

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

the class EvaluatesToConstantPredicate method handleEquivalence.

private Formula handleEquivalence(final Equivalence formula, final boolean topLevel) {
    final FormulaFactory f = formula.factory();
    final Formula left = formula.left();
    final Formula right = formula.right();
    final Formula leftResult = innerTest(left, false);
    if (leftResult.isConstantFormula()) {
        return isVerum(leftResult) ? innerTest(right, topLevel) : innerTest(f.not(right), topLevel);
    }
    final Formula rightResult = innerTest(right, false);
    if (rightResult.isConstantFormula()) {
        if (topLevel) {
            return f.constant(!this.evaluatesToTrue);
        }
        return isVerum(rightResult) ? leftResult : f.not(leftResult);
    }
    return f.equivalence(leftResult, rightResult);
}

Example 23 with Formula

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

the class EvaluatesToConstantPredicate method handleNot.

private Formula handleNot(final Not formula, final boolean topLevel) {
    final FormulaFactory f = formula.factory();
    final Formula opResult = innerTest(formula.operand(), false);
    if (topLevel && !opResult.isConstantFormula()) {
        return f.constant(!this.evaluatesToTrue);
    }
    return opResult.isConstantFormula() ? f.constant(isFalsum(opResult)) : f.not(opResult);
}

Example 24 with Formula

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

the class EvaluatesToConstantPredicate method handleImplication.

private Formula handleImplication(final Implication formula, final boolean topLevel) {
    final FormulaFactory f = formula.factory();
    final Formula left = formula.left();
    final Formula right = formula.right();
    final Formula leftResult = innerTest(left, false);
    if (leftResult.isConstantFormula()) {
        if (this.evaluatesToTrue) {
            return isFalsum(leftResult) ? f.verum() : innerTest(right, topLevel);
        } else {
            return isVerum(leftResult) ? innerTest(right, topLevel) : f.verum();
        }
    }
    if (!this.evaluatesToTrue && topLevel) {
        return f.verum();
    }
    final Formula rightResult = innerTest(right, false);
    if (rightResult.isConstantFormula()) {
        return isVerum(rightResult) ? f.verum() : f.not(leftResult);
    }
    return f.implication(leftResult, rightResult);
}

Example 25 with Formula

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

the class EvaluatesToConstantPredicate method handleAnd.

private Formula handleAnd(final And formula, final boolean topLevel) {
    final FormulaFactory f = formula.factory();
    final List<Formula> nops = new ArrayList<>();
    for (final Formula op : formula) {
        final Formula opResult = innerTest(op, this.evaluatesToTrue && topLevel);
        if (isFalsum(opResult)) {
            return f.falsum();
        }
        if (!opResult.isConstantFormula()) {
            if (this.evaluatesToTrue && topLevel) {
                return f.falsum();
            }
            nops.add(opResult);
        }
    }
    return f.and(nops);
}