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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 pseudo boolean algorithms described in:
20   * A fast pseudo-Boolean constraint solver Chai, D.; Kuehlmann, A.
21   * Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on
22   * Volume 24, Issue 3, March 2005 Page(s): 305 - 317
23   * 
24   * and 
25   * Heidi E. Dixon, 2004. Automating Pseudo-Boolean Inference within a DPLL 
26   * Framework. Ph.D. Dissertation, University of Oregon.
27   *******************************************************************************/
28  package org.sat4j.pb.core;
29  
30  import java.math.BigInteger;
31  
32  import org.sat4j.minisat.core.AssertingClauseGenerator;
33  import org.sat4j.minisat.core.IOrder;
34  import org.sat4j.minisat.core.LearningStrategy;
35  import org.sat4j.minisat.core.RestartStrategy;
36  import org.sat4j.minisat.core.SearchParams;
37  import org.sat4j.minisat.core.Solver;
38  import org.sat4j.pb.IPBSolver;
39  import org.sat4j.pb.ObjectiveFunction;
40  import org.sat4j.pb.orders.VarOrderHeapObjective;
41  import org.sat4j.specs.ContradictionException;
42  import org.sat4j.specs.IConstr;
43  import org.sat4j.specs.IVec;
44  import org.sat4j.specs.IVecInt;
45  
46  public abstract class PBSolver extends Solver<PBDataStructureFactory> implements
47  		IPBSolver {
48  
49  	private ObjectiveFunction objf;
50  
51  	/**
52       * 
53       */
54  	private static final long serialVersionUID = 1L;
55  
56  	protected PBSolverStats stats;
57  
58  	public PBSolver(AssertingClauseGenerator acg,
59  			LearningStrategy<PBDataStructureFactory> learner,
60  			PBDataStructureFactory dsf, IOrder order, RestartStrategy restarter) {
61  		super(acg, learner, dsf, order, restarter);
62  		stats = new PBSolverStats();
63  		initStats(stats);
64  	}
65  
66  	public PBSolver(AssertingClauseGenerator acg,
67  			LearningStrategy<PBDataStructureFactory> learner,
68  			PBDataStructureFactory dsf, SearchParams params, IOrder order,
69  			RestartStrategy restarter) {
70  		super(acg, learner, dsf, params, order, restarter);
71  		stats = new PBSolverStats();
72  		initStats(stats);
73  	}
74  
75  	public IConstr addPseudoBoolean(IVecInt literals, IVec<BigInteger> coeffs,
76  			boolean moreThan, BigInteger degree) throws ContradictionException {
77  		IVecInt vlits = dimacs2internal(literals);
78  		assert vlits.size() == literals.size();
79  		assert literals.size() == coeffs.size();
80  		return addConstr(dsfactory.createPseudoBooleanConstraint(vlits, coeffs,
81  				moreThan, degree));
82  	}
83  
84  	public void setObjectiveFunction(ObjectiveFunction obj) {
85  		objf = obj;
86  		IOrder order = getOrder();
87  		if (order instanceof VarOrderHeapObjective) {
88  			((VarOrderHeapObjective) order).setObjectiveFunction(obj);
89  		}
90  	}
91  
92  	public ObjectiveFunction getObjectiveFunction() {
93  		return objf;
94  	}
95  }