1 /******************************************************************************* 2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre 3 * 4 * All rights reserved. This program and the accompanying materials 5 * are made available under the terms of the Eclipse Public License v1.0 6 * which accompanies this distribution, and is available at 7 * http://www.eclipse.org/legal/epl-v10.html 8 * 9 * Alternatively, the contents of this file may be used under the terms of 10 * either the GNU Lesser General Public License Version 2.1 or later (the 11 * "LGPL"), in which case the provisions of the LGPL are applicable instead 12 * of those above. If you wish to allow use of your version of this file only 13 * under the terms of the LGPL, and not to allow others to use your version of 14 * this file under the terms of the EPL, indicate your decision by deleting 15 * the provisions above and replace them with the notice and other provisions 16 * required by the LGPL. If you do not delete the provisions above, a recipient 17 * may use your version of this file under the terms of the EPL or the LGPL. 18 * 19 * Based on the original MiniSat specification from: 20 * 21 * An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the 22 * Sixth International Conference on Theory and Applications of Satisfiability 23 * Testing, LNCS 2919, pp 502-518, 2003. 24 * 25 * See www.minisat.se for the original solver in C++. 26 * 27 *******************************************************************************/ 28 package org.sat4j.opt; 29 30 import org.sat4j.core.VecInt; 31 import org.sat4j.specs.ContradictionException; 32 import org.sat4j.specs.IConstr; 33 import org.sat4j.specs.IOptimizationProblem; 34 import org.sat4j.specs.ISolver; 35 import org.sat4j.specs.IVecInt; 36 37 /** 38 * Computes a solution that satisfies the maximum of clauses. 39 * 40 * @author daniel 41 * 42 */ 43 public class MaxSatDecorator extends AbstractSelectorVariablesDecorator 44 implements IOptimizationProblem { 45 46 /** 47 * 48 */ 49 private static final long serialVersionUID = 1L; 50 51 52 public MaxSatDecorator(ISolver solver) { 53 super(solver); 54 } 55 56 57 @Override 58 public void setExpectedNumberOfClauses(int nb) { 59 super.setExpectedNumberOfClauses(nb); 60 lits.ensure(nb); 61 } 62 63 64 @Override 65 public IConstr addClause(IVecInt literals) throws ContradictionException { 66 int newvar = nborigvars + ++nbnewvar; 67 lits.push(newvar); 68 literals.push(newvar); 69 return super.addClause(literals); 70 } 71 72 @Override 73 public void reset() { 74 nbnewvar = 0; 75 lits.clear(); 76 super.reset(); 77 } 78 79 public boolean hasNoObjectiveFunction() { 80 return false; 81 } 82 83 public boolean nonOptimalMeansSatisfiable() { 84 return false; 85 } 86 87 public Number calculateObjective() { 88 counter = 0; 89 for (int q : prevfullmodel) { 90 if (q > nborigvars) { 91 counter++; 92 } 93 } 94 return counter; 95 } 96 97 private final IVecInt lits = new VecInt(); 98 99 private int counter; 100 101 public void discard() throws ContradictionException { 102 super.addAtMost(lits, counter - 1); 103 } 104 105 }