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
26 package org.sat4j.minisat.orders;
27
28 import java.util.ArrayList;
29 import java.util.Collections;
30 import java.util.List;
31
32 import org.sat4j.minisat.core.ILits2;
33
34 /**
35 * @author leberre To change the template for this generated type comment go to
36 * Window>Preferences>Java>Code Generation>Code and Comments
37 */
38 public class MyOrder extends VarOrder<ILits2> {
39
40 private static final long serialVersionUID = 1L;
41
42 /*
43 * (non-Javadoc)
44 *
45 * @see org.sat4j.minisat.IHeuristics#init()
46 */
47 @Override
48 public void init() {
49 super.init();
50 List<ValuedLit> v = new ArrayList<ValuedLit>(order.length);
51 int id;
52 for (int i = 1; i < order.length; i++) {
53 id = order[i];
54 v.add(new ValuedLit(id,lits.nBinaryClauses(id) + lits.nBinaryClauses(id ^ 1)));
55 }
56 Collections.sort(v);
57 // System.out.println(v);
58 for (int i = 0; i < v.size(); i++) {
59 ValuedLit t = v.get(i);
60 order[i + 1] = t.id;
61 int index = t.id >> 1;
62 varpos[index] = i + 1;
63 }
64 lastVar = 1;
65 }
66
67 @Override
68 public String toString() {
69 return "Init VSIDS order with binary clause occurrences."; //$NON-NLS-1$
70 }
71 }