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 static org.sat4j.core.LiteralsUtils.neg;
31
32 import org.sat4j.minisat.core.ILits;
33 import org.sat4j.specs.IVecInt;
34
35 /**
36 * @author daniel
37 * @since 2.1
38 */
39 public class LearntHTClause extends HTClause {
40
41 public LearntHTClause(IVecInt ps, ILits voc) {
42 super(ps, voc);
43 }
44
45 /**
46 *
47 */
48 private static final long serialVersionUID = 1L;
49
50 /*
51 * (non-Javadoc)
52 *
53 * @see org.sat4j.minisat.constraints.cnf.WLClause#register()
54 */
55 public void register() {
56 // looking for the literal to put in tail
57 if (middleLits.length > 0) {
58 int maxi = 0;
59 int maxlevel = voc.getLevel(middleLits[0]);
60 for (int i = 1; i < middleLits.length; i++) {
61 int level = voc.getLevel(middleLits[i]);
62 if (level > maxlevel) {
63 maxi = i;
64 maxlevel = level;
65 }
66 }
67 if (maxlevel > voc.getLevel(tail)) {
68 int l = tail;
69 tail = middleLits[maxi];
70 middleLits[maxi] = l;
71 }
72 }
73 // attach both head and tail literals.
74 voc.watch(neg(head), this);
75 voc.watch(neg(tail), this);
76
77 }
78
79 public boolean learnt() {
80 return true;
81 }
82
83 public void setLearnt() {
84 // do nothing
85 }
86
87 public void forwardActivity(double claInc) {
88
89 }
90
91 /**
92 * @param claInc
93 */
94 public void incActivity(double claInc) {
95 activity += claInc;
96 }
97 }