| Clover coverage report - |
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| Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
| SingleSolutionDetector.java | - | 92,3% | 100% | 93,8% |
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| 1 | package org.sat4j.tools; | |
| 2 | ||
| 3 | import org.sat4j.core.VecInt; | |
| 4 | import org.sat4j.specs.ContradictionException; | |
| 5 | import org.sat4j.specs.IConstr; | |
| 6 | import org.sat4j.specs.ISolver; | |
| 7 | import org.sat4j.specs.IVecInt; | |
| 8 | import org.sat4j.specs.TimeoutException; | |
| 9 | ||
| 10 | /** | |
| 11 | * This solver decorator allows to detect whether or not the set of constraints | |
| 12 | * available in the solver has only one solution or not. | |
| 13 | * | |
| 14 | * NOTE THAT THIS DECORATOR CANNOT BE USED WITH SOLVERS USING SPECIFIC | |
| 15 | * DATA STRUCTURES FOR BINARY OR TERNARY CLAUSES! | |
| 16 | * | |
| 17 | * <code> | |
| 18 | SingleSolutionDetector problem = | |
| 19 | new SingleSolutionDetector(SolverFactory.newMiniSAT()); | |
| 20 | // feed problem/solver as usual | |
| 21 | ||
| 22 | if (problem.isSatisfiable()) { | |
| 23 | if (problem.hasASingleSolution()) { | |
| 24 | // great, the instance has a unique solution | |
| 25 | int [] uniquesolution = problem.getModel(); | |
| 26 | } else { | |
| 27 | // too bad, got more than one | |
| 28 | } | |
| 29 | } | |
| 30 | * </code> | |
| 31 | * @author leberre | |
| 32 | * | |
| 33 | */ | |
| 34 | public class SingleSolutionDetector extends SolverDecorator { | |
| 35 | ||
| 36 | /** | |
| 37 | * | |
| 38 | */ | |
| 39 | private static final long serialVersionUID = 1L; | |
| 40 | ||
| 41 | 2 | public SingleSolutionDetector(ISolver solver) { |
| 42 | 2 | super(solver); |
| 43 | } | |
| 44 | ||
| 45 | /** | |
| 46 | * Please use that method only after a positive answer from | |
| 47 | * isSatisfiable() (else a runtime exception will be launched). | |
| 48 | * | |
| 49 | * @return true iff there is only one way to satisfy all the constraints | |
| 50 | * in the solver. | |
| 51 | * @throws TimeoutException | |
| 52 | */ | |
| 53 | 3 | public boolean hasASingleSolution() throws TimeoutException { |
| 54 | 3 | return hasASingleSolution(new VecInt()); |
| 55 | } | |
| 56 | ||
| 57 | /** | |
| 58 | * Please use that method only after a positive answer from | |
| 59 | * isSatisfiable(assumptions) (else a runtime exception will be launched). | |
| 60 | * | |
| 61 | * @param assumptions a set of literals (dimacs numbering) that must be | |
| 62 | * satisfied. | |
| 63 | * @return true iff there is only one way to satisfy all the constraints | |
| 64 | * in the solver using the provided set of assumptions. | |
| 65 | * @throws TimeoutException | |
| 66 | */ | |
| 67 | 6 | public boolean hasASingleSolution(IVecInt assumptions) |
| 68 | throws TimeoutException { | |
| 69 | 6 | int [] firstmodel = model(); |
| 70 | assert firstmodel != null; | |
| 71 | 4 | IVecInt clause = new VecInt(firstmodel.length); |
| 72 | 4 | for (int q : firstmodel) { |
| 73 | 8 | clause.push(-q); |
| 74 | } | |
| 75 | 4 | boolean result = false; |
| 76 | 4 | try { |
| 77 | 4 | IConstr added = addClause(clause); |
| 78 | 4 | result = !isSatisfiable(assumptions); |
| 79 | 4 | removeConstr(added); |
| 80 | } catch (ContradictionException e) { | |
| 81 | 0 | result = true; |
| 82 | } | |
| 83 | 4 | return result; |
| 84 | } | |
| 85 | } |
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