代码 | 自适应大邻域搜索系列之(5) - ALNS_Iteration_Status和ALNS

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代码 | 自适应大邻域搜索系列之(5) - ALNS_Iteration_Status和ALNS_Parameters的代码解析

前言

上一篇推文说了，后面的代码难度直线下降，各位小伙伴可以放去n的100次方心了。今天讲讲一些细枝末节，就是前面一直有提到的参数和一些状态的记录代码。这个简单啦，小编也不作过多解释了。大家直接看代码都能看懂，不过小编还是会把逻辑结构给大家梳理出来的。好了，开始干活。

01 ALNS_Iteration_Status

这个类，咳咳，不是抽象类了哈。主要用来记录ALNS迭代过程中的一些中间变量和状态等。主要是成员变量，成员函数都是简单的getter（获取成员变量的接口）或者setter（设置成员变量的接口）。所以这里就把成员变量贴出来好了，各个变量记录的内容注释也写得很详细，小编就不做多赘述以免扰乱了大家看代码的心。

private://! Id of the iteration corresponding to this status.size_t iterationId;//! Number of iteration since the last improvement of the BKSsize_t nbIterationWithoutImprovement;//! Number of iteration since the last improvement of the BKS//! or the last reload of the best known solution.size_t nbIterationWithoutImprovementSinceLastReload;//! Number of iterations since the last improvement of the current//! solution.size_t nbIterationWithoutImprovementCurrent;//! Number of iterations without transition.size_t nbIterationWithoutTransition;//! Indicate if a new best solution has been obtained.State newBestSolution;//! Indicate if the new solution has been accepted as the//! current solution.State acceptedAsCurrentSolution;//! Indicate if the new solution is already known.State alreadyKnownSolution;//! Indicate if the new solution improve the current solution.State improveCurrentSolution;//! Indicate if a local search operator has been used.State localSearchUsed;//! Indicate if solution has been improved by local search.State improveByLocalSearch;//! Indicate if the solution has already been repaired.State alreadyRepaired;//! Indicate if the new solution has already been destroyed.State alreadyDestroyed;};

02 ALNS_Parameters

该类是ALNS运行过程中的一些参数设置，和上面的ALNS_Iteration_Status差不多，主要功能集中在成员变量上，成员函数都是简单的getter（获取成员变量的接口）或者setter（设置成员变量的接口）。照例把成员变量贴出来吧~

public://! Enumeration representing the various kind of stopping criteria.//! MAX_IT: the maximum number of iterations.//! MAX_RT: the maximum run time.//! MAX_IT_NO_IMP: the maximum number of iterations without improvement.//! ALL: a mix of the MAX_IT, MAX_RT and MAX_IT_NO_IMP.enum StoppingCriteria {MAX_IT,MAX_RT,MAX_IT_NO_IMP,ALL};//! An enumeration listing a set of packaged AcceptanceModule Implementation.enum AcceptanceCriterioKind {SA};
protected://! Maximum number of iterations performed by the ALNS.size_t maxNbIterations;//! Maximum running time of the ALNS.double maxRunningTime;//! Maximum number of iterations without any improvement.size_t maxNbIterationsNoImp;//! Which stopping criterion should be used.StoppingCriteria stopCrit;//! Indicate if noise should be used.bool noise;//! Indicate after how many iterations should the scores of//! the operators be recomputed.size_t timeSegmentsIt;//! Indicate the number of iterations that should be performed//! before reinitialization of the scores of the operators.size_t nbItBeforeReinit;//! score adjustment parameter in case the last remove-insert//! operation resulted in a new global best solutionint sigma1;//! score adjustment parameter in case that the last remove-insert//! operation resulted in a solution that has not been accepted before and//! the objective value is better than the objective value of current solutionint sigma2;//! score adjustment parameter in case that the last remove-insert//! operation resulted in a solution that has not been accepted before and such//! that the score objective value is worse than the one of current solution but//! the solution was accepted.int sigma3;//! reaction factor 0 <= rho <= 1 for the update of the weights of the//! operators.double rho;//! The minimum possible weight for an operator.double minimumWeight;//! The maximum possible weight for an operator.double maximumWeight;//! Indicates the probability of using noised operators.double probabilityOfNoise;//! Kind of acceptance criterion used.AcceptanceCriterioKind acKind;//! patht to the configuration file of the acceptance criterion.std::string acPath;//! path to the file where the global stats have to be saved.std::string statsGlobPath;//! path to the file where the operators stats have to be saved.std::string statsOpPath;//! Indicate every each iteration logging is done. 不懂看后面。int logFrequency;//! A set of forbidden operators. 不懂看后面。std::vector<std::string> forbidenOperators;//! A set of forbidden local search operators. 不懂看后面。std::vector<std::string> forbidenLsOperators;//! The minimum percentage of the solution destroyed by the destroy operators.int minDestroyPerc;//! The maximum percentage of the solution destroyed by the destroy operators.int maxDestroyPerc;//! Indicate after how many iterations without improvement//! does the best known solution is reloaded.size_t reloadFrequency;//! Indicate if local search should be used.bool performLocalSearch;//! When the optimization process start, the parameters//! should not be modified. lock is set to true when the//! optimization begin. If the setter of the value//! of one parameter is called while lock is true, an//! error is raised.bool lock;};

不过有几个变量大家看了注释可能还不太明白是干嘛用的。在这里再解释一下。

logFrequency，隔多少次迭代输出一下当前的信息。直接给大家上两个图让大家心领神会一下：