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
29 package org.sat4j.tools.encoding;
30
31 import org.sat4j.specs.ContradictionException;
32 import org.sat4j.specs.IConstr;
33 import org.sat4j.specs.ISolver;
34 import org.sat4j.specs.IVecInt;
35
36 /**
37 * This class allows the use of different encodings for different cardinality
38 * constraints.
39 *
40 * @author stephanieroussel
41 * @since 2.3.1
42 */
43 public class Policy extends EncodingStrategyAdapter {
44
45 private final Sequential seq = new Sequential();
46 private final Binary binary = new Binary();
47 private final Product product = new Product();
48 private final Commander commander = new Commander();
49
50 @Override
51 public IConstr addAtMost(ISolver solver, IVecInt literals, int k)
52 throws ContradictionException {
53
54 // Commander commander = new Commander();
55 // Product product = new Product();
56 if (k == 0 || literals.size() == 1) {
57 // will propagate unit literals
58 return super.addAtMost(solver, literals, k);
59 }
60 if (literals.size() <= 1) {
61 throw new UnsupportedOperationException(
62 "requires at least 2 literals");
63 }
64 if (k == 1) {
65 // return ladder.addAtMostOne(solver, literals);
66 // return binary.addAtMostOne(solver, literals);
67 return commander.addAtMostOne(solver, literals);
68 // return product.addAtMostOne(solver, literals);
69 }
70 // return seq.addAtMost(solver, literals, k);
71 // return product.addAtMost(solver, literals, k);
72 return commander.addAtMost(solver, literals, k);
73 }
74
75 @Override
76 public IConstr addExactly(ISolver solver, IVecInt literals, int n)
77 throws ContradictionException {
78 Ladder ladder = new Ladder();
79 if (n == 1) {
80 return ladder.addExactlyOne(solver, literals);
81 }
82
83 return super.addExactly(solver, literals, n);
84 }
85
86 }