View Javadoc

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 pseudo boolean algorithms described in:
20   * A fast pseudo-Boolean constraint solver Chai, D.; Kuehlmann, A.
21   * Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on
22   * Volume 24, Issue 3, March 2005 Page(s): 305 - 317
23   * 
24   * and 
25   * Heidi E. Dixon, 2004. Automating Pseudo-Boolean Inference within a DPLL 
26   * Framework. Ph.D. Dissertation, University of Oregon.
27   *******************************************************************************/
28  package org.sat4j.pb.core;
29  
30  import java.math.BigInteger;
31  
32  import org.sat4j.minisat.core.AssertingClauseGenerator;
33  import org.sat4j.minisat.core.ILits;
34  import org.sat4j.minisat.core.IOrder;
35  import org.sat4j.minisat.core.LearningStrategy;
36  import org.sat4j.minisat.core.RestartStrategy;
37  import org.sat4j.minisat.core.SearchParams;
38  import org.sat4j.minisat.core.Solver;
39  import org.sat4j.pb.IPBSolver;
40  import org.sat4j.pb.ObjectiveFunction;
41  import org.sat4j.pb.orders.VarOrderHeapObjective;
42  import org.sat4j.specs.ContradictionException;
43  import org.sat4j.specs.IConstr;
44  import org.sat4j.specs.IVec;
45  import org.sat4j.specs.IVecInt;
46  
47  public abstract class PBSolver<L extends ILits> extends
48          Solver<L, PBDataStructureFactory<L>> implements IPBSolver {
49  
50      /**
51       * 
52       */
53      private static final long serialVersionUID = 1L;
54  
55      public PBSolver(AssertingClauseGenerator acg,
56              LearningStrategy<L, PBDataStructureFactory<L>> learner,
57              PBDataStructureFactory<L> dsf, IOrder<L> order,
58              RestartStrategy restarter) {
59          super(acg, learner, dsf, order, restarter);
60      }
61  
62      public PBSolver(AssertingClauseGenerator acg,
63              LearningStrategy<L, PBDataStructureFactory<L>> learner,
64              PBDataStructureFactory<L> dsf, SearchParams params,
65              IOrder<L> order, RestartStrategy restarter) {
66          super(acg, learner, dsf, params, order, restarter);
67      }
68  
69      public IConstr addPseudoBoolean(IVecInt literals, IVec<BigInteger> coeffs,
70              boolean moreThan, BigInteger degree) throws ContradictionException {
71          IVecInt vlits = dimacs2internal(literals);
72          assert vlits.size() == literals.size();
73          assert literals.size() == coeffs.size();
74          return addConstr(dsfactory.createPseudoBooleanConstraint(vlits, coeffs,
75                  moreThan, degree));
76      }
77  
78      /**
79       * list of variables for which the solver must provide an explanation for
80       * the unsatisfiability if any
81       */
82      protected IVecInt listOfVariables;
83  
84      public void setListOfVariablesForExplanation(IVecInt lv) {
85          listOfVariables = lv;
86      }
87  
88      public String getExplanation() {
89          return "";
90      }
91  
92      public void setObjectiveFunction(ObjectiveFunction obj) {
93          IOrder<L> order = getOrder();
94          if (order instanceof VarOrderHeapObjective) {
95              ((VarOrderHeapObjective) order).setObjectiveFunction(obj);
96          }
97      }
98  }