arXiv:2508.05957cs.LGcs.AI2025-08被引 1

用强化学习动态剪枝,提升决策树泛化能力

Multi-Armed Bandits-Based Optimization of Decision Trees

  • 将剪枝视为探索与利用问题,用多臂老虎机算法选择最优剪枝节点
  • 在多个基准数据集上预测性能优于传统剪枝方法
  • 适合小样本复杂数据,可提升模型对未知数据的鲁棒性

决策树若无适当约束,易变得过于复杂并过拟合,捕捉噪声而非可泛化的模式。剪枝是优化决策树的关键步骤,既能降低复杂度,又能减少过拟合概率。传统的剪枝方法如代价-复杂度剪枝(CCP)和简化误差剪枝(REP)多基于贪心策略,仅关注即时性能提升,可能导致长期泛化能力下降,尤其在小而复杂的数据集上表现不佳。为此,本文提出一种基于多臂老虎机(MAB)的剪枝方法,属于强化学习技术,通过动态剪枝生成泛化能力更强的决策树。该方法将剪枝过程建模为探索-利用问题,利用MAB算法根据每次剪枝动作的反馈,寻找最优剪枝分支节点。在多个基准数据集上的实验表明,该方法相比传统方法具有更优的预测性能,验证了使用MAB实现动态、概率化剪枝的潜力,从而优化基于决策树的模型。

原文摘要 · Abstract (English)

Decision trees, without appropriate constraints, can easily become overly complex and prone to overfit, capturing noise rather than generalizable patterns. To resolve this problem,pruning operation is a crucial part in optimizing decision trees, as it not only reduces the complexity of trees but also decreases the probability of generating overfit models. The conventional pruning techniques like Cost-Complexity Pruning (CCP) and Reduced Error Pruning (REP) are mostly based on greedy approaches that focus on immediate gains in performance while pruning nodes of the decision tree. However, this might result in a lower generalization in the long run, compromising the robust ability of the tree model when introduced to unseen data samples, particularly when trained with small and complex datasets. To address this challenge, we are proposing a Multi-Armed Bandits (MAB)-based pruning approach, a reinforcement learning (RL)-based technique, that will dynamically prune the tree to generate an optimal decision tree with better generalization. Our proposed approach assumes the pruning process as an exploration-exploitation problem, where we are utilizing the MAB algorithms to find optimal branch nodes to prune based on feedback from each pruning actions. Experimental evaluation on several benchmark datasets, demonstrated that our proposed approach results in better predictive performance compared to the traditional ones. This suggests the potential of utilizing MAB for a dynamic and probabilistic way of decision tree pruning, in turn optimizing the decision tree-based model.

决策树剪枝强化学习多臂老虎机

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