1 /*
2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2006 Daniel Le Berre
3 *
4 * Based on the original minisat specification from:
5 *
6 * An extensible SAT solver. Niklas E?n and Niklas S?rensson. Proceedings of the
7 * Sixth International Conference on Theory and Applications of Satisfiability
8 * Testing, LNCS 2919, pp 502-518, 2003.
9 *
10 * This library is free software; you can redistribute it and/or modify it under
11 * the terms of the GNU Lesser General Public License as published by the Free
12 * Software Foundation; either version 2.1 of the License, or (at your option)
13 * any later version.
14 *
15 * This library is distributed in the hope that it will be useful, but WITHOUT
16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
17 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
18 * details.
19 *
20 * You should have received a copy of the GNU Lesser General Public License
21 * along with this library; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 *
24 */
25 package org.sat4j.minisat.constraints.cnf;
26
27 import org.sat4j.minisat.core.ILits;
28 import org.sat4j.specs.IVecInt;
29
30 public class DefaultWLClause extends WLClause {
31
32 private boolean learnt;
33
34 public DefaultWLClause(IVecInt ps, ILits voc) {
35 super(ps, voc);
36 }
37
38 /**
39 *
40 */
41 private static final long serialVersionUID = 1L;
42
43 /**
44 * declares this clause as learnt
45 *
46 */
47 public void setLearnt() {
48 learnt = true;
49 }
50
51 /*
52 * (non-Javadoc)
53 *
54 * @see org.sat4j.minisat.datatype.Constr#learnt()
55 */
56 public boolean learnt() {
57 return learnt;
58 }
59
60 /**
61 * Register this clause which means watching the necessary literals If the
62 * clause is learnt, setLearnt() must be called before a call to register()
63 *
64 * @see #setLearnt()
65 */
66 public void register() {
67 assert lits.length > 1;
68 if (learnt) {
69 // prendre un deuxieme litt???ral ??? surveiller
70 int maxi = 1;
71 int maxlevel = voc.getLevel(lits[1]);
72 for (int i = 2; i < lits.length; i++) {
73 int level = voc.getLevel(lits[i]);
74 if (level > maxlevel) {
75 maxi = i;
76 maxlevel = level;
77 }
78 }
79 int l = lits[1];
80 lits[1] = lits[maxi];
81 lits[maxi] = l;
82 }
83
84 // ajoute la clause a la liste des clauses control???es.
85 voc.watch(lits[0] ^ 1, this);
86 voc.watch(lits[1] ^ 1, this);
87 }
88
89 }