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.learning;
29
30 import org.sat4j.minisat.core.Constr;
31 import org.sat4j.minisat.core.DataStructureFactory;
32 import org.sat4j.minisat.core.ILits;
33
34 /**
35 * A learning scheme for learning constraints of size smaller than a given
36 * constant.
37 *
38 * @author leberre
39 */
40 public class FixedLengthLearning<L extends ILits,D extends DataStructureFactory<L>> extends LimitedLearning<L,D> {
41
42 private static final long serialVersionUID = 1L;
43
44 private int maxlength;
45
46 private int bound;
47
48 public FixedLengthLearning() {
49 this(3);
50 }
51
52 public FixedLengthLearning(int maxlength) {
53 this.maxlength = maxlength;
54 }
55
56 /*
57 * (non-Javadoc)
58 *
59 * @see org.sat4j.minisat.LimitedLearning#learningCondition(org.sat4j.minisat.Constr)
60 */
61 @Override
62 public void init() {
63 setBound(maxlength);
64 }
65
66 public void setMaxLength(int v) {
67 maxlength = v;
68 }
69
70 public int getMaxLength() {
71 return maxlength;
72 }
73
74 @Override
75 public String toString() {
76 return "Limit learning to clauses of size smaller or equal to " //$NON-NLS-1$
77 + maxlength;
78 }
79
80 protected void setBound(int newbound) {
81 bound = newbound;
82 }
83
84 @Override
85 protected boolean learningCondition(Constr constr) {
86 return constr.size() <= bound;
87 }
88
89 }