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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 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.minisat.constraints.cnf;
29  
30  import org.sat4j.minisat.core.ILits;
31  import org.sat4j.specs.IVecInt;
32  
33  public final class LearntWLClause extends WLClause {
34  
35  	public LearntWLClause(IVecInt ps, ILits voc) {
36  		super(ps, voc);
37  	}
38  
39  	/**
40       * 
41       */
42  	private static final long serialVersionUID = 1L;
43  
44  	/*
45  	 * (non-Javadoc)
46  	 * 
47  	 * @see org.sat4j.minisat.constraints.cnf.WLClause#register()
48  	 */
49  	public void register() {
50  		assert lits.length > 1;
51  		// prendre un deuxieme litt???ral ??? surveiller
52  		int maxi = 1;
53  		int maxlevel = voc.getLevel(lits[1]);
54  		for (int i = 2; i < lits.length; i++) {
55  			int level = voc.getLevel(lits[i]);
56  			if (level > maxlevel) {
57  				maxi = i;
58  				maxlevel = level;
59  			}
60  		}
61  		int l = lits[1];
62  		lits[1] = lits[maxi];
63  		lits[maxi] = l;
64  
65  		// ajoute la clause a la liste des clauses control???es.
66  		voc.watch(lits[0] ^ 1, this);
67  		voc.watch(lits[1] ^ 1, this);
68  
69  	}
70  
71  	public boolean learnt() {
72  		return true;
73  	}
74  
75  	public void setLearnt() {
76  		// do nothing
77  	}
78  
79  	/**
80  	 * @since 2.1
81  	 */
82  	public void forwardActivity(double claInc) {
83  
84  	}
85  
86  	/**
87  	 * @param claInc
88  	 */
89  	public void incActivity(double claInc) {
90  		activity += claInc;
91  	}
92  }