在有限样本下精准定位多个突变点,揭示位置关系对检测难度的关键影响。
The Sample Complexity of Multiple Change Point Identification under Bandit Feedback
- 自适应选择查询点,先定位可能含突变点的区间,再精细逼近位置。
- 理论与实验表明,样本复杂度由跳跃大小和突变点相对位置共同决定。
- 适用于需要高精度突变检测且样本成本敏感的动态系统分析场景。
我们研究在贝叶斯反馈下的多突变点定位问题。一个未知的分段常数函数在紧区间上可逐次自适应查询,每次查询返回函数的带噪评估值。目标是在给定精度η和置信度1−δ下,识别出指定数量的不连续点(即突变点),同时最小化采样次数。本文提出一种自适应算法:首先检测可能包含突变点的区间,然后精炼其位置至η精度。我们建立了非渐近的样本预算上界,并给出了相应的下界。已有研究指出,当δ→0时,跳跃幅度决定渐近样本复杂度。本文揭示,在一般δ和η条件下,复杂度由跳跃大小与突变点相对位置共同决定。
原文摘要 · Abstract (English)
We study multiple change point localization under bandit feedback. An unknown piecewise-constant function on a compact interval can be queried sequentially at adaptively chosen inputs, and each query returns a noisy evaluation of the function. The goal is to identify a prescribed number of discontinuities, known as change points, within a target precision $η$ and confidence level $1-δ$, while using as few samples as possible. We propose an adaptive algorithm that first detects intervals likely to contain change points and then refines their locations to precision $η$. We establish non-asymptotic upper bounds on its sample budget, together with corresponding lower bounds. Prior work shows that jump magnitudes alone determine the asymptotic sample complexity as $δ\to 0$. We reveal that this picture is incomplete beyond this regime. We demonstrate, both empirically and theoretically, that for general $δ$ and $η$, the complexity is jointly governed by the jumps and the relative positions of the change points.
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