Timefold构造启发式中移动选择及pickEarlyType失效问题咨询

我尝试在Timefold中使用Recommended fit，需要设置4个规划变量，希望在构造启发式中结合笛卡尔积（cartesian product）和顺序移动。但无论将哪个移动选择器放在首位，构造启发式只会运行第一个，其余移动选择均被忽略。目前我只能通过组合笛卡尔积选择器来设置所有4个变量，但该方式扩展性不佳。请问这是API的限制还是存在解决方法？此外，pickEarlyType似乎也被忽略，即使在结果列表中较早找到可行解，仍会返回所有可能的组合。

配置代码如下：

<scoreDirectorFactory>
  <constraintProviderClass>MyConstraintProvider</constraintProviderClass>
  <initializingScoreTrend>ONLY_DOWN</initializingScoreTrend>
</scoreDirectorFactory>

<termination>
  <unimprovedSecondsSpentLimit>180</unimprovedSecondsSpentLimit>
</termination>

<constructionHeuristic>
  <constructionHeuristicType>FIRST_FIT_DECREASING</constructionHeuristicType>
  <cartesianProductMoveSelector>
    <changeMoveSelector>
      <valueSelector variableName="timeBlock">
        <filterClass>TimeBlockSelectionFilter</filterClass>
      </valueSelector>
    </changeMoveSelector>
    <changeMoveSelector>
      <valueSelector variableName="worker">
        <filterClass>NoNullVariableAndNoKompetencer</filterClass>
      </valueSelector>
    </changeMoveSelector>
  </cartesianProductMoveSelector>
  <changeMoveSelector>
    <valueSelector variableName="room">
      <filterClass>NoNullVariable</filterClass>
    </valueSelector>
  </changeMoveSelector>
  <changeMoveSelector>
    <valueSelector variableName="assistant">
      <filterClass>NoNullVariable</filterClass>
    </valueSelector>
  </changeMoveSelector>
  <forager>
    <pickEarlyType>FIRST_FEASIBLE_SCORE_OR_NON_DETERIORATING_HARD</pickEarlyType>
  </forager>
</constructionHeuristic>

1. 多移动选择器被忽略的问题：并非API限制，是配置方式错误 #

构造启发式默认只会使用<constructionHeuristic>下的第一个移动选择器，并列的后续选择器会被忽略。要实现「先执行笛卡尔积移动，再依次执行单个变量的顺序移动」，需要将每个移动逻辑拆分为独立的构造启发式阶段，用<phase>标签嵌套每个阶段的配置。

这种分阶段的方式不仅能实现顺序执行，还能针对每个阶段单独调整策略（比如不同的constructionHeuristicType或筛选器），扩展性更好。

2. 修改后的配置示例 #

<scoreDirectorFactory>
  <constraintProviderClass>MyConstraintProvider</constraintProviderClass>
  <initializingScoreTrend>ONLY_DOWN</initializingScoreTrend>
</scoreDirectorFactory>

<termination>
  <unimprovedSecondsSpentLimit>180</unimprovedSecondsSpentLimit>
</termination>

<!-- 阶段1：用笛卡尔积同时分配timeBlock和worker -->
<phase>
  <constructionHeuristic>
    <constructionHeuristicType>FIRST_FIT_DECREASING</constructionHeuristicType>
    <cartesianProductMoveSelector>
      <changeMoveSelector>
        <valueSelector variableName="timeBlock">
          <filterClass>TimeBlockSelectionFilter</filterClass>
        </valueSelector>
      </changeMoveSelector>
      <changeMoveSelector>
        <valueSelector variableName="worker">
          <filterClass>NoNullVariableAndNoKompetencer</filterClass>
        </valueSelector>
      </changeMoveSelector>
    </cartesianProductMoveSelector>
    <forager>
      <pickEarlyType>FIRST_FEASIBLE_SCORE_OR_NON_DETERIORATING_HARD</pickEarlyType>
    </forager>
  </constructionHeuristic>
</phase>

<!-- 阶段2：单独分配room -->
<phase>
  <constructionHeuristic>
    <constructionHeuristicType>FIRST_FIT_DECREASING</constructionHeuristicType>
    <changeMoveSelector>
      <valueSelector variableName="room">
        <filterClass>NoNullVariable</filterClass>
      </valueSelector>
    </changeMoveSelector>
    <forager>
      <pickEarlyType>FIRST_FEASIBLE_SCORE_OR_NON_DETERIORATING_HARD</pickEarlyType>
    </forager>
  </constructionHeuristic>
</phase>

<!-- 阶段3：单独分配assistant -->
<phase>
  <constructionHeuristic>
    <constructionHeuristicType>FIRST_FIT_DECREASING</constructionHeuristicType>
    <changeMoveSelector>
      <valueSelector variableName="assistant">
        <filterClass>NoNullVariable</filterClass>
      </valueSelector>
    </changeMoveSelector>
    <forager>
      <pickEarlyType>FIRST_FEASIBLE_SCORE_OR_NON_DETERIORATING_HARD</pickEarlyType>
    </forager>
  </constructionHeuristic>
</phase>

3. pickEarlyType未生效的问题排查 #

• 阶段独立配置：确保每个构造启发式阶段都单独配置<forager>，全局的<forager>不会自动作用于所有阶段。
• 可行解识别：检查你的约束提供者（MyConstraintProvider）是否正确标记了「可行解」——即硬约束完全满足的状态。如果硬约束始终不满足，pickEarlyType会继续搜索所有候选。
• 移动选择逻辑：确认筛选器（如TimeBlockSelectionFilter）没有过滤掉所有可行的候选值，导致没有符合条件的可行移动供pickEarlyType触发。

内容的提问来源于stack exchange，提问作者Christian