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.orders;
31
32 import static org.sat4j.core.LiteralsUtils.neg;
33 import static org.sat4j.core.LiteralsUtils.var;
34
35 import java.math.BigInteger;
36
37 import org.sat4j.minisat.core.IPhaseSelectionStrategy;
38 import org.sat4j.minisat.orders.PhaseInLastLearnedClauseSelectionStrategy;
39 import org.sat4j.minisat.orders.VarOrderHeap;
40 import org.sat4j.pb.ObjectiveFunction;
41 import org.sat4j.specs.IVec;
42 import org.sat4j.specs.IVecInt;
43
44 public class VarOrderHeapObjective extends VarOrderHeap implements
45 IOrderObjective {
46
47 /**
48 *
49 */
50 private static final long serialVersionUID = 1L;
51
52 private ObjectiveFunction obj;
53
54 public VarOrderHeapObjective() {
55 this(new PhaseInLastLearnedClauseSelectionStrategy());
56 }
57
58 public VarOrderHeapObjective(IPhaseSelectionStrategy strategy) {
59 super(strategy);
60 }
61
62 public void setObjectiveFunction(ObjectiveFunction obj) {
63 this.obj = obj;
64 }
65
66 @Override
67 public void init() {
68 super.init();
69 if (this.obj != null) {
70 IVecInt vars = this.obj.getVars();
71 IVec<BigInteger> coefs = this.obj.getCoeffs();
72 for (int i = 0; i < vars.size(); i++) {
73 int dimacsLiteral = vars.get(i);
74 if (this.lits.belongsToPool(Math.abs(dimacsLiteral))) {
75 int p = this.lits.getFromPool(dimacsLiteral);
76 BigInteger c = coefs.get(i);
77 if (c.signum() < 0) {
78 p = neg(p);
79 }
80 int var = var(p);
81 this.activity[var] = c.bitLength() < Long.SIZE ? c.abs()
82 .longValue() : Long.MAX_VALUE;
83 if (this.heap.inHeap(var)) {
84 this.heap.increase(var);
85 } else {
86 this.heap.insert(var);
87 }
88 this.phaseStrategy.init(var, neg(p));
89 }
90 }
91 }
92 }
93
94 @Override
95 public String toString() {
96 return super.toString() + " taking into account the objective function";
97 }
98
99 }