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

Example 36 with Formula

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

the class HypergraphGenerator method fromCNF.

/**
 * Generates a hypergraph from a CNF given as a list of clauses.  Each variable is represented by a node in the
 * hypergraph, each clause is represented by a hyperedge between all variables of the clause.
 * @param cnf the list of clauses of the CNF for the hypergraph
 * @return the hypergraph for the CNF formula
 */
public static Hypergraph<Variable> fromCNF(final List<Formula> cnf) {
    final Hypergraph<Variable> hypergraph = new Hypergraph<>();
    final Map<Variable, HypergraphNode<Variable>> nodes = new HashMap<>();
    for (final Formula clause : cnf) {
        switch(clause.type()) {
            case PBC:
            case EQUIV:
            case IMPL:
            case NOT:
            case AND:
                throw new IllegalStateException("Unexpected element in clause: " + clause);
            case LITERAL:
            case OR:
                addClause(clause, hypergraph, nodes);
                break;
        }
    }
    return hypergraph;
}

Example 37 with Formula

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

the class AIGTransformation method transformOr.

private Formula transformOr(final Or or) {
    Formula aig = or.transformationCacheEntry(AIG);
    if (aig == null) {
        final LinkedHashSet<Formula> nops = new LinkedHashSet<>(or.numberOfOperands());
        for (final Formula op : or) {
            nops.add(f.not(apply(op, cache)));
        }
        aig = f.not(f.and(nops));
        if (cache) {
            or.setTransformationCacheEntry(AIG, aig);
            aig.setPredicateCacheEntry(PredicateCacheEntry.IS_AIG, true);
        }
    }
    return aig;
}

Example 38 with Formula

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

the class AIGTransformation method transformAnd.

private Formula transformAnd(final And and) {
    Formula aig = and.transformationCacheEntry(AIG);
    if (aig == null) {
        final LinkedHashSet<Formula> nops = new LinkedHashSet<>(and.numberOfOperands());
        for (final Formula op : and) {
            nops.add(apply(op, cache));
        }
        aig = f.and(nops);
        if (cache) {
            and.setTransformationCacheEntry(AIG, aig);
            aig.setPredicateCacheEntry(PredicateCacheEntry.IS_AIG, true);
        }
    }
    return aig;
}

Example 39 with Formula

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

the class AIGTransformation method transformImplication.

private Formula transformImplication(final Implication impl) {
    Formula aig = impl.transformationCacheEntry(AIG);
    if (aig == null) {
        aig = f.not(f.and(apply(impl.left(), cache), f.not(apply(impl.right(), cache))));
        if (cache) {
            impl.setTransformationCacheEntry(AIG, aig);
            aig.setPredicateCacheEntry(PredicateCacheEntry.IS_AIG, true);
        }
    }
    return aig;
}

Example 40 with Formula

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

the class AIGTransformation method transformNot.

private Formula transformNot(final Not not) {
    Formula aig = not.transformationCacheEntry(AIG);
    if (aig == null) {
        aig = f.not(apply(not.operand(), cache));
        if (cache) {
            not.setTransformationCacheEntry(AIG, aig);
            aig.setPredicateCacheEntry(PredicateCacheEntry.IS_AIG, true);
        }
    }
    return aig;
}