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The pb library contains algorithms for solving pseudo boolean optimization problems.
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/*******************************************************************************
 * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU Lesser General Public License Version 2.1 or later (the
 * "LGPL"), in which case the provisions of the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of the LGPL, and not to allow others to use your version of
 * this file under the terms of the EPL, indicate your decision by deleting
 * the provisions above and replace them with the notice and other provisions
 * required by the LGPL. If you do not delete the provisions above, a recipient
 * may use your version of this file under the terms of the EPL or the LGPL.
 * 
 * Based on the pseudo boolean algorithms described in:
 * A fast pseudo-Boolean constraint solver Chai, D.; Kuehlmann, A.
 * Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on
 * Volume 24, Issue 3, March 2005 Page(s): 305 - 317
 * 
 * and 
 * Heidi E. Dixon, 2004. Automating Pseudo-Boolean Inference within a DPLL 
 * Framework. Ph.D. Dissertation, University of Oregon.
 *******************************************************************************/
package org.sat4j.pb.tools;

import java.math.BigInteger;
import java.util.Collection;

import org.sat4j.core.Vec;
import org.sat4j.core.VecInt;
import org.sat4j.pb.IPBSolver;
import org.sat4j.pb.OptToPBSATAdapter;
import org.sat4j.pb.PBSolverDecorator;
import org.sat4j.specs.IVec;
import org.sat4j.specs.IVecInt;

public class LexicoHelper extends DependencyHelper {

	private final LexicoDecoratorPB lexico;

	public LexicoHelper(IPBSolver solver) {
		super(new OptToPBSATAdapter(new LexicoDecoratorPB(solver)));
		lexico = (LexicoDecoratorPB) ((PBSolverDecorator) getSolver())
				.decorated();
	}

	public LexicoHelper(IPBSolver solver, boolean explanationEnabled,
			boolean canonicalOptFunctionEnabled) {
		super(new OptToPBSATAdapter(new LexicoDecoratorPB(solver)),
				explanationEnabled, canonicalOptFunctionEnabled);
		lexico = (LexicoDecoratorPB) ((PBSolverDecorator) getSolver())
				.decorated();
	}

	public LexicoHelper(IPBSolver solver, boolean explanationEnabled) {
		super(new OptToPBSATAdapter(new LexicoDecoratorPB(solver)),
				explanationEnabled);
		lexico = (LexicoDecoratorPB) ((PBSolverDecorator) getSolver())
				.decorated();
	}

	public void addCriterion(Collection things) {
		IVecInt literals = new VecInt(things.size());
		for (T thing : things) {
			literals.push(getIntValue(thing));
		}
		lexico.addCriterion(literals);
	}

	public void addWeightedCriterion(Collection> things) {
		IVecInt literals = new VecInt(things.size());
		IVec coefs = new Vec(things.size());
		for (WeightedObject wo : things) {
			literals.push(getIntValue(wo.thing));
			coefs.push(wo.getWeight());
		}
		lexico.addCriterion(literals, coefs);
	}

	public boolean isOptimal() {
		return ((OptToPBSATAdapter) getSolver()).isOptimal();
	}
}