1 /*
2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2006 Daniel Le Berre
3 *
4 * Based on the original minisat specification from:
5 *
6 * An extensible SAT solver. Niklas E?n and Niklas S?rensson. Proceedings of the
7 * Sixth International Conference on Theory and Applications of Satisfiability
8 * Testing, LNCS 2919, pp 502-518, 2003.
9 *
10 * This library is free software; you can redistribute it and/or modify it under
11 * the terms of the GNU Lesser General Public License as published by the Free
12 * Software Foundation; either version 2.1 of the License, or (at your option)
13 * any later version.
14 *
15 * This library is distributed in the hope that it will be useful, but WITHOUT
16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
17 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
18 * details.
19 *
20 * You should have received a copy of the GNU Lesser General Public License
21 * along with this library; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 *
24 */
25 package org.sat4j.tools;
26
27 import java.io.Serializable;
28
29 import org.sat4j.specs.ContradictionException;
30
31 /**
32 * Converts Dimacs problems in array format (without the terminating 0) to
33 * Dimacs Strings.
34 *
35 * Adaptation of org.sat4j.reader.DimacsReader.
36 *
37 * @author dlb
38 * @author or
39 * @author fuhs
40 */
41 public class DimacsArrayToDimacsConverter implements Serializable {
42
43 private static final long serialVersionUID = 1L;
44
45 // counter for the number of clauses that occur in the SAT instance
46 protected int clauses;
47
48 protected StringBuilder dimacs; // stores the dimacs string while under
49 // construction
50
51 private final int bufSize; // initial capacity of dimacs
52
53 public DimacsArrayToDimacsConverter(int bufSize) {
54 this.bufSize = bufSize;
55 }
56
57 protected boolean handleConstr(int gateType, int output, int[] inputs)
58 throws ContradictionException {
59 for (int var : inputs) {
60 this.dimacs.append(var);
61 this.dimacs.append(" ");
62 }
63 this.dimacs.append("0\n");
64 ++this.clauses;
65 return true;
66 }
67
68 /**
69 * @param gateType
70 * gateType[i] is the type of gate i according to the Extended
71 * Dimacs specs; ignored in DimacsArrayReader, but important for
72 * inheriting classes
73 * @param outputs
74 * outputs[i] is the number of the output; ignored in
75 * DimacsArrayReader
76 * @param inputs
77 * inputs[i] contains the clauses in DimacsArrayReader; an
78 * overriding class might have it contain the inputs of the
79 * current gate
80 * @param maxVar
81 * the maximum number of assigned ids
82 * @throws ContradictionException
83 * si le probleme est trivialement inconsitant
84 */
85 public String parseInstance(int[] gateType, int[] outputs, int[][] inputs,
86 int maxVar) throws ContradictionException {
87 init();
88 this.dimacs.append(maxVar);
89 this.dimacs.append(" ");
90
91 // the first character to be replaced is saved
92 // (7 = "p cnf ".length() + " ".length())
93 int firstCharPos = 7 + Integer.toString(maxVar).length();
94
95 this.dimacs.append(" ");
96 // 20 blanks; if the number of clauses ever exceeds 10^21-1, this needs
97 // to be altered. But that would require BigIntegers anyway.
98
99 this.dimacs.append("\n");
100 for (int i = 0; i < outputs.length; ++i) {
101 handleConstr(gateType[i], outputs[i], inputs[i]);
102 }
103 String numClauses = Integer.toString(this.clauses);
104 int numClausesLength = numClauses.length();
105 for (int i = 0; i < numClausesLength; ++i) {
106 this.dimacs.setCharAt(firstCharPos + i, numClauses.charAt(i));
107 }
108 String result = this.dimacs.toString();
109 this.dimacs = null; // let the garbage collector at it
110 return result;
111 }
112
113 protected void init() {
114 this.dimacs = new StringBuilder(this.bufSize);
115 this.dimacs.append("p cnf ");
116 this.clauses = 0;
117 }
118
119 public String decode(int[] model) {
120 StringBuilder stb = new StringBuilder();
121 for (int i = 0; i < model.length; i++) {
122 stb.append(model[i]);
123 stb.append(" ");
124 }
125 stb.append("0");
126 return stb.toString();
127 }
128 }