用于车辆路线的 OptaPlanner

Question

我正在尝试使用 OptaPlanner 解决 VRP。我用约束提供者、规划实体和规划解决方案等编写了所有代码。问题是，我试图通过

        SolverConfig solverConfig = new SolverConfig();
        solverConfig.withSolutionClass(Solution.class);
        solverConfig.withEntityClasses(Stop.class, Standstill.class);
        ScoreDirectorFactoryConfig scoreDirectorFactoryConfig = new ScoreDirectorFactoryConfig();
        scoreDirectorFactoryConfig.setConstraintProviderClass(VrpConstraintProvider.class);

        solverConfig.withScoreDirectorFactory(scoreDirectorFactoryConfig);

        SolverFactory<Solution> solverFactory = SolverFactory.create(solverConfig);
        Solver<Solution> solver = solverFactory.buildSolver();

        Solution solution = solver.solve(solutionDef);

但这会导致无休止的等待解决方案。有什么想法是什么原因吗？提前致谢。

Answer 1

您尚未配置求解器终止条件。例如，如果您希望求解器求解 60 秒，请添加以下内容：

solverConfig.withTerminationConfig(new TerminationConfig().withSecondsSpentLimit(60L));

请注意，在您提供的示例中，求解器在主线程上运行并阻塞它，直到满足终止条件并自动停止求解。由于您的示例中没有这样的条件，它会永远解决并阻塞线程。

或者，使用SolverManager API 异步解决问题（在工作线程上）：

int problemId = 1;
SolverManager<Solution, Integer> solverManager = SolverManager.create(
        solverConfig, new SolverManagerConfig());
SolverJob<Solution, Integer> solverJob = solverManager.solve(problemId, solutionDef);
// wait some time, then terminate solver manager
solverManager.terminateEarly(problemId);
Solution bestSolution = solverJob.getFinalBestSolution();