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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.pb;
31  
32  import static org.junit.Assert.assertTrue;
33  
34  import java.math.BigInteger;
35  
36  import org.junit.Test;
37  import org.sat4j.core.Vec;
38  import org.sat4j.core.VecInt;
39  import org.sat4j.specs.ContradictionException;
40  import org.sat4j.specs.IProblem;
41  import org.sat4j.specs.IVec;
42  import org.sat4j.specs.IVecInt;
43  import org.sat4j.specs.TimeoutException;
44  
45  public class MikolasTest {
46      static boolean solve(PseudoOptDecorator optproblem) throws TimeoutException {
47          boolean isSatisfiable = false;
48  
49          try {
50              while (optproblem.admitABetterSolution()) {
51                  if (!isSatisfiable) {
52                      if (optproblem.nonOptimalMeansSatisfiable()) {
53                          if (optproblem.hasNoObjectiveFunction()) {
54                              return true;
55                          }
56                      }
57                      isSatisfiable = true;
58                  }
59                  optproblem.discardCurrentSolution();
60              }
61          } catch (ContradictionException ex) {
62              assertTrue(isSatisfiable);
63          }
64          return isSatisfiable;
65      }
66  
67      public static IVecInt vector(int... ls) {
68          return new VecInt(ls);
69      }
70  
71      public static IVec<BigInteger> constant_vector(final BigInteger value,
72              int sz) {
73          IVec<BigInteger> ones = new Vec<BigInteger>(sz);
74          for (int index = 0; index < sz; ++index) {
75              ones.push(value);
76          }
77          return ones;
78      }
79  
80      public static void print_model(IProblem solver) {
81          for (int index = 1; index <= solver.nVars(); ++index) {
82              System.err.print((solver.model(index) ? "+" : "-") + index + " ");
83          }
84      }
85  
86      @Test
87      public void testLexicoOptimizationWithPseudoOptDecorator()
88              throws ContradictionException, TimeoutException {
89          PseudoOptDecorator solver = new PseudoOptDecorator(
90                  org.sat4j.pb.SolverFactory.newDefault());
91          solver.newVar(8);
92          solver.setObjectiveFunction(new ObjectiveFunction(vector(6, 7, 8),
93                  constant_vector(BigInteger.valueOf(-1), 3)));
94          System.err.println(solver.getObjectiveFunction());
95  
96          solver.addClause(vector(-3, 6));
97          solver.addClause(vector(-1, -6));
98          solver.addClause(vector(-4, 7));
99          solver.addClause(vector(1, -7));
100         solver.addClause(vector(-5, 8));
101         solver.addClause(vector(-2, -8));
102 
103         // only this, crashes
104         solver.addClause(vector(1, 2, 3));
105         assertTrue(solve(solver));
106         print_model(solver);
107         System.err.println();
108         solver.addClause(vector(1));
109         assertTrue(solve(solver));
110     }
111 
112 }