Examples with LNGVector org.logicng.collections.LNGVector used on opensource projects

Example 16 with LNGVector

use of org.logicng.collections.LNGVector in project LogicNG by logic-ng.

the class PBAdderNetworks method encode.

@Override
public List<Formula> encode(final LNGVector<Literal> lits, final LNGIntVector coeffs, final int rhs, final List<Formula> formula) {
    this.formula = formula;
    final LNGVector<Literal> result = new LNGVector<>();
    final LNGVector<LinkedList<Literal>> buckets = new LNGVector<>();
    final int nb = ldInt(rhs);
    for (int iBit = 0; iBit < nb; ++iBit) {
        buckets.push(new LinkedList<>());
        result.push(null);
        for (int iVar = 0; iVar < lits.size(); iVar++) {
            if (((1 << iBit) & coeffs.get(iVar)) != 0) {
                buckets.back().push(lits.get(iVar));
            }
        }
    }
    this.adderTree(buckets, result);
    final LNGBooleanVector kBits = this.numToBits(buckets.size(), rhs);
    this.lessThanOrEqual(result, kBits, formula);
    return formula;
}

Example 17 with LNGVector

use of org.logicng.collections.LNGVector in project LogicNG by logic-ng.

the class PBEncoder method encode.

/**
 * Builds a pseudo Boolean constraint of the form {@code c_1 * lit_1 + c_2 * lit_2 + ... + c_n * lit_n >= k}.
 * @param lits   the literals {@code lit_1 ... lit_n}
 * @param coeffs the coefficients {@code c_1 ... c_n}
 * @param rhs    the right hand side {@code k} of the constraint
 * @return the CNF encoding of the pseudo Boolean constraint
 * @throws IllegalArgumentException if the right hand side of the cardinality constraint is negative or
 *                                  larger than the number of literals
 */
protected List<Formula> encode(final Literal[] lits, final int[] coeffs, final int rhs) {
    if (rhs == Integer.MAX_VALUE) {
        throw new IllegalArgumentException("Overflow in the Encoding");
    }
    if (rhs < 0) {
        return Collections.singletonList(this.f.falsum());
    }
    final LNGVector<Literal> simplifiedLits = new LNGVector<>();
    final LNGIntVector simplifiedCoeffs = new LNGIntVector();
    final List<Formula> result = new ArrayList<>();
    if (rhs == 0) {
        for (final Literal lit : lits) {
            result.add(lit.negate());
        }
        return result;
    }
    for (int i = 0; i < lits.length; i++) {
        if (coeffs[i] <= rhs) {
            simplifiedLits.push(lits[i]);
            simplifiedCoeffs.push(coeffs[i]);
        } else {
            result.add(lits[i].negate());
        }
    }
    if (simplifiedLits.size() <= 1) {
        return result;
    }
    switch(this.config().pbEncoder) {
        case SWC:
        case BEST:
            if (this.swc == null) {
                this.swc = new PBSWC(this.f);
            }
            return this.swc.encode(simplifiedLits, simplifiedCoeffs, rhs, result);
        case BINARY_MERGE:
            return new PBBinaryMerge(this.f, this.config()).encode(simplifiedLits, simplifiedCoeffs, rhs, result);
        case ADDER_NETWORKS:
            if (this.adderNetworks == null) {
                this.adderNetworks = new PBAdderNetworks(this.f);
            }
            return this.adderNetworks.encode(simplifiedLits, simplifiedCoeffs, rhs, result);
        default:
            throw new IllegalStateException("Unknown pseudo-Boolean encoder: " + this.config().pbEncoder);
    }
}