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
36 /**
37 * Minisat original restart strategy.
38 *
39 * @author leberre
40 *
41 */
42 public final class MiniSATRestarts implements RestartStrategy {
43
44 /**
45 *
46 */
47 private static final long serialVersionUID = 1L;
48
49 private double nofConflicts;
50
51 private SearchParams params;
52
53 private int conflictcount;
54
55 public void init(SearchParams theParams) {
56 this.params = theParams;
57 this.nofConflicts = theParams.getInitConflictBound();
58 }
59
60 public long nextRestartNumberOfConflict() {
61 return Math.round(this.nofConflicts);
62 }
63
64 public void onRestart() {
65 this.nofConflicts *= this.params.getConflictBoundIncFactor();
66 }
67
68 @Override
69 public String toString() {
70 return "MiniSAT restarts strategy";
71 }
72
73 public boolean shouldRestart() {
74 return this.conflictcount >= this.nofConflicts;
75 }
76
77 public void onBackjumpToRootLevel() {
78 this.conflictcount = 0;
79 }
80
81 public void reset() {
82 this.conflictcount = 0;
83 }
84
85 public void newConflict() {
86 this.conflictcount++;
87 }
88
89 public SearchParams getSearchParams() {
90 return this.params;
91 }
92
93 public void newLearnedClause(Constr learned, int trailLevel) {
94 }
95 }