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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 org.sat4j.minisat.core.AssertingClauseGenerator;
31  import org.sat4j.minisat.core.IOrder;
32  import org.sat4j.minisat.core.LearningStrategy;
33  import org.sat4j.pb.constraints.pb.ConflictMapSwitchToClause;
34  import org.sat4j.pb.constraints.pb.IConflict;
35  import org.sat4j.pb.constraints.pb.PBConstr;
36  
37  public class PBSolverCautious extends PBSolverCP {
38  
39  	private static final long serialVersionUID = 1L;
40  	public static final int BOUND = 10;
41  
42  	public PBSolverCautious(AssertingClauseGenerator acg,
43  			LearningStrategy<PBDataStructureFactory> learner,
44  			PBDataStructureFactory dsf, IOrder order) {
45  		super(acg, learner, dsf, order);
46  		ConflictMapSwitchToClause.UPPERBOUND = BOUND;
47  	}
48  
49  	public PBSolverCautious(AssertingClauseGenerator acg,
50  			LearningStrategy<PBDataStructureFactory> learner,
51  			PBDataStructureFactory dsf, IOrder order, int bound) {
52  		super(acg, learner, dsf, order);
53  		ConflictMapSwitchToClause.UPPERBOUND = bound;
54  	}
55  
56  	@Override
57  	IConflict chooseConflict(PBConstr myconfl, int level) {
58  		return ConflictMapSwitchToClause.createConflict(myconfl, level);
59  	}
60  
61  	@Override
62  	public String toString(String prefix) {
63  		return super.toString(prefix)
64  				+ "\n"
65  				+ prefix
66  				+ "When dealing with too large coefficients, simplify asserted PB constraints to clauses";
67  	}
68  
69  	@Override
70  	protected void updateNumberOfReductions(IConflict confl) {
71  		stats.numberOfReductions += ((ConflictMapSwitchToClause) confl)
72  				.getNumberOfReductions();
73  	}
74  
75  	@Override
76  	protected void updateNumberOfReducedLearnedConstraints(IConflict confl) {
77  		if (((ConflictMapSwitchToClause) confl).hasBeenReduced())
78  			stats.numberOfLearnedConstraintsReduced++;
79  	}
80  
81  }