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.maxsat;
31
32 import org.sat4j.core.ASolverFactory;
33 import org.sat4j.minisat.constraints.MixedDataStructureDanielWL;
34 import org.sat4j.minisat.core.DataStructureFactory;
35 import org.sat4j.minisat.core.SearchParams;
36 import org.sat4j.minisat.core.Solver;
37 import org.sat4j.minisat.learning.MiniSATLearning;
38 import org.sat4j.minisat.orders.VarOrderHeap;
39 import org.sat4j.minisat.restarts.MiniSATRestarts;
40 import org.sat4j.pb.IPBSolver;
41
42 public class SolverFactory extends ASolverFactory<IPBSolver> {
43
44 private static final long serialVersionUID = 1L;
45
46 private static SolverFactory instance;
47
48 /**
49 * Builds a SAT solver for the MAX sat evaluation. Full clause learning, no
50 * restarts,
51 *
52 * @return a
53 */
54 public static Solver<DataStructureFactory> newMiniMaxSAT() {
55 MiniSATLearning<DataStructureFactory> learning = new MiniSATLearning<DataStructureFactory>();
56 Solver<DataStructureFactory> solver = new Solver<DataStructureFactory>(
57 learning, new MixedDataStructureDanielWL(), new SearchParams(
58 1.2, 100000), new VarOrderHeap(), new MiniSATRestarts());
59 learning.setDataStructureFactory(solver.getDSFactory());
60 learning.setVarActivityListener(solver);
61 return solver;
62 }
63
64 /**
65 * Private contructor. Use singleton method instance() instead.
66 *
67 * @see #instance()
68 */
69 private SolverFactory() {
70
71 }
72
73 private static synchronized void createInstance() {
74 if (instance == null) {
75 instance = new SolverFactory();
76 }
77 }
78
79 /**
80 * Access to the single instance of the factory.
81 *
82 * @return the singleton of that class.
83 */
84 public static SolverFactory instance() {
85 if (instance == null) {
86 createInstance();
87 }
88 return instance;
89 }
90
91 @Override
92 public IPBSolver defaultSolver() {
93 return newDefault();
94 }
95
96 @Override
97 public IPBSolver lightSolver() {
98 return newLight();
99 }
100
101 public static IPBSolver newDefault() {
102 return org.sat4j.pb.SolverFactory.newDefault();
103 }
104
105 public static IPBSolver newLight() {
106 return org.sat4j.pb.SolverFactory.newLight();
107 }
108 }