论文标题
通过黑盒建议追逐凸面的身体和功能
Chasing Convex Bodies and Functions with Black-Box Advice
论文作者
论文摘要
我们考虑了通过Black-Box建议追逐凸功能的问题,在线决策者旨在最大程度地降低规范矢量空间中决策的总成本和切换的总成本,并得到了黑盒建议的帮助,例如机器学习算法的决策。决策者在表现良好的情况下(称为$ \ textIt {Entermentimency} $时,都可以寻求与建议相当的成本,同时也确保最差的$ \ textit {robultness} $即使建议是对抗性的。我们首先考虑算法的常见范式,这些算法在建议的决策和竞争性算法之间切换,表明该类别中没有算法可以改善3-符合性的同时保持稳定。然后,我们提出了两种新颖的算法,这些算法通过利用问题的凸度来绕过这一限制。第一个,Interp,成就$(\ sqrt {2}+ε)$ - 一致性和$ \ Mathcal {o}(\ frac {c} {c} {ε^2})$ - 任何$ε> 0 $的鲁棒性,在任何$ε> 0 $中,$ c $在$ c $的情况下,是colorithm a convex for convex foldef convex sub consing consing consing consing或a a n a consing consing或a a。第二个,bdinterp,达到$(1+ε)$ - 一致性和$ \ MATHCAL {o}(\ frac {cd}ε)$ - 当问题界定直径$ d $时,稳健性。此外,我们表明BDINTERP在成本功能为$α$ polyhedral的特殊情况下实现了近乎最佳的一致性 - 持久性权衡。
We consider the problem of convex function chasing with black-box advice, where an online decision-maker aims to minimize the total cost of making and switching between decisions in a normed vector space, aided by black-box advice such as the decisions of a machine-learned algorithm. The decision-maker seeks cost comparable to the advice when it performs well, known as $\textit{consistency}$, while also ensuring worst-case $\textit{robustness}$ even when the advice is adversarial. We first consider the common paradigm of algorithms that switch between the decisions of the advice and a competitive algorithm, showing that no algorithm in this class can improve upon 3-consistency while staying robust. We then propose two novel algorithms that bypass this limitation by exploiting the problem's convexity. The first, INTERP, achieves $(\sqrt{2}+ε)$-consistency and $\mathcal{O}(\frac{C}{ε^2})$-robustness for any $ε> 0$, where $C$ is the competitive ratio of an algorithm for convex function chasing or a subclass thereof. The second, BDINTERP, achieves $(1+ε)$-consistency and $\mathcal{O}(\frac{CD}ε)$-robustness when the problem has bounded diameter $D$. Further, we show that BDINTERP achieves near-optimal consistency-robustness trade-off for the special case where cost functions are $α$-polyhedral.