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| package org.sat4j.reader.csp; |
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| |
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3 |
| import java.util.HashMap; |
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4 |
| import java.util.Map; |
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| |
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6 |
| import org.sat4j.core.VecInt; |
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7 |
| import org.sat4j.specs.ContradictionException; |
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8 |
| import org.sat4j.specs.ISolver; |
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9 |
| import org.sat4j.specs.IVec; |
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| import org.sat4j.specs.IVecInt; |
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11 |
| |
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12 |
| public class BinarySupportsACEncoding extends SupportsDirectEncoding { |
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13 |
| |
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14 |
0
| public BinarySupportsACEncoding(int arity, int nbtuples) {
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15 |
0
| super(arity, nbtuples);
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16 |
0
| if (arity != 2)
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17 |
0
| throw new UnsupportedOperationException(
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| "Works only for binary constraints"); |
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19 |
| } |
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| |
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21 |
0
| @Override
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22 |
| public void toClause(ISolver solver, IVec<Var> scope, IVec<Evaluable> vars) |
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23 |
| throws ContradictionException { |
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24 |
0
| Map<Integer, IVecInt> supportsa = new HashMap<Integer, IVecInt>();
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25 |
0
| Map<Integer, IVecInt> supportsb = new HashMap<Integer, IVecInt>();
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26 |
| |
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27 |
0
| for (int i = 0; i < tuples.length; i++) {
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| assert arity == 2; |
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29 |
0
| int va = tuples[i][0];
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30 |
0
| int vb = tuples[i][1];
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31 |
0
| addSupport(va, vars.get(1), vb, supportsa);
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32 |
0
| addSupport(vb, vars.get(0), va, supportsb);
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33 |
| } |
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34 |
| |
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35 |
0
| generateClauses(vars.get(0), supportsa, solver);
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36 |
0
| generateClauses(vars.get(1), supportsb, solver);
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37 |
| } |
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38 |
| |
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39 |
0
| private void addSupport(int head, Evaluable v, int value,
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40 |
| Map<Integer, IVecInt> supports) { |
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41 |
0
| IVecInt sup = supports.get(head);
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42 |
0
| if (sup == null) {
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43 |
0
| sup = new VecInt();
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44 |
0
| supports.put(head, sup);
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45 |
| } |
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46 |
0
| sup.push(v.translate(value));
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47 |
| } |
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48 |
| |
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49 |
0
| private void generateClauses(Evaluable v, Map<Integer, IVecInt> supports,
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50 |
| ISolver solver) throws ContradictionException { |
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51 |
0
| IVecInt clause = new VecInt();
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52 |
0
| for (int key : v.domain()) {
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53 |
0
| clause.clear();
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54 |
0
| IVecInt support = supports.get(key);
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55 |
0
| clause.push(-v.translate(key));
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56 |
0
| if (support != null) {
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57 |
0
| for (int i : support)
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58 |
0
| clause.push(i);
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59 |
| } |
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60 |
0
| solver.addClause(clause);
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61 |
| } |
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62 |
| } |
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63 |
| } |
