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;
29
30 import org.sat4j.core.ASolverFactory;
31 import org.sat4j.minisat.constraints.MixedDataStructureDanielWL;
32 import org.sat4j.minisat.core.DataStructureFactory;
33 import org.sat4j.minisat.core.SearchParams;
34 import org.sat4j.minisat.core.Solver;
35 import org.sat4j.minisat.learning.MiniSATLearning;
36 import org.sat4j.minisat.orders.RSATPhaseSelectionStrategy;
37 import org.sat4j.minisat.orders.VarOrderHeap;
38 import org.sat4j.minisat.restarts.ArminRestarts;
39 import org.sat4j.minisat.uip.FirstUIP;
40 import org.sat4j.specs.ISolver;
41
42 /**
43 * That class is the entry point to the default, best performing configuration
44 * of SAT4J. Since there is only one concrete reference per strategy used inside
45 * the solver, it is a good start for people willing to reduce the library to
46 * the minimal number of classes needed to run a SAT solver. The main method
47 * allow to run the solver from the command line.
48 *
49 * @author leberre
50 * @since 2.2
51 */
52 public class LightFactory extends ASolverFactory<ISolver> {
53 private static final long serialVersionUID = 1460304168178023681L;
54 private static LightFactory instance;
55
56 private static synchronized void createInstance() {
57 if (instance == null) {
58 instance = new LightFactory();
59 }
60 }
61
62 /**
63 * Access to the single instance of the factory.
64 *
65 * @return the singleton of that class.
66 */
67 public static LightFactory instance() {
68 if (instance == null) {
69 createInstance();
70 }
71 return instance;
72 }
73
74 @Override
75 public ISolver defaultSolver() {
76 MiniSATLearning<DataStructureFactory> learning = new MiniSATLearning<DataStructureFactory>();
77 Solver<DataStructureFactory> solver = new Solver<DataStructureFactory>(
78 new FirstUIP(), learning, new MixedDataStructureDanielWL(),
79 new VarOrderHeap(new RSATPhaseSelectionStrategy()),
80 new ArminRestarts());
81 learning.setSolver(solver);
82 solver.setSimplifier(solver.EXPENSIVE_SIMPLIFICATION);
83 solver.setSearchParams(new SearchParams(1.1, 100));
84 return solver;
85 }
86
87 @Override
88 public ISolver lightSolver() {
89 return defaultSolver();
90 }
91
92 public static void main(final String[] args) {
93 BasicLauncher<ISolver> lanceur = new BasicLauncher<ISolver>(
94 LightFactory.instance());
95 if (args.length != 1) {
96 lanceur.usage();
97 return;
98 }
99 lanceur.run(args);
100 System.exit(lanceur.getExitCode().value());
101 }
102
103 }