1 /*******************************************************************************
2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004, 2012 Artois University and CNRS
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 * Contributors:
28 * CRIL - initial API and implementation
29 *******************************************************************************/
30 package org.sat4j.minisat.learning;
31
32 import org.sat4j.minisat.core.Constr;
33 import org.sat4j.minisat.core.DataStructureFactory;
34
35 /**
36 * A learning scheme for learning constraints of size smaller than a given
37 * constant.
38 *
39 * @author leberre
40 */
41 public final class FixedLengthLearning<D extends DataStructureFactory> extends
42 LimitedLearning<D> {
43
44 private static final long serialVersionUID = 1L;
45
46 private int maxlength;
47
48 private int bound;
49
50 public FixedLengthLearning() {
51 this(3);
52 }
53
54 public FixedLengthLearning(int maxlength) {
55 this.maxlength = maxlength;
56 }
57
58 /*
59 * (non-Javadoc)
60 *
61 * @see
62 * org.sat4j.minisat.LimitedLearning#learningCondition(org.sat4j.minisat
63 * .Constr)
64 */
65 @Override
66 public void init() {
67 setBound(this.maxlength);
68 }
69
70 public void setMaxLength(int v) {
71 this.maxlength = v;
72 }
73
74 public int getMaxLength() {
75 return this.maxlength;
76 }
77
78 @Override
79 public String toString() {
80 return "Limit learning to clauses of size smaller or equal to " //$NON-NLS-1$
81 + this.maxlength;
82 }
83
84 protected void setBound(int newbound) {
85 this.bound = newbound;
86 }
87
88 @Override
89 protected boolean learningCondition(Constr constr) {
90 return constr.size() <= this.bound;
91 }
92
93 }