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.restarts;
31
32 import org.sat4j.minisat.core.Constr;
33 import org.sat4j.minisat.core.RestartStrategy;
34 import org.sat4j.minisat.core.SearchParams;
35 import org.sat4j.minisat.core.SolverStats;
36
37 public class FixedPeriodRestarts implements RestartStrategy {
38
39 /**
40 *
41 */
42 private static final long serialVersionUID = 1L;
43
44 private long conflictCount;
45
46 private long period;
47
48 public void reset() {
49 conflictCount = 0;
50 }
51
52 public void newConflict() {
53 conflictCount++;
54 }
55
56 public void init(SearchParams params, SolverStats stats) {
57 this.conflictCount = 0;
58 }
59
60 @Deprecated
61 public long nextRestartNumberOfConflict() {
62 return period;
63 }
64
65 public boolean shouldRestart() {
66 return conflictCount >= period;
67 }
68
69 public void onRestart() {
70 this.conflictCount = 0;
71 }
72
73 public void onBackjumpToRootLevel() {
74 }
75
76 public void newLearnedClause(Constr learned, int trailLevel) {
77 }
78
79 public long getPeriod() {
80 return period;
81 }
82
83 public void setPeriod(long period) {
84 this.period = period;
85 }
86
87 @Override
88 public String toString() {
89 return "constant restarts strategy every " + this.period + " conflicts";
90 }
91 }