Parameter-free, dynamic, and strongly-adaptive online learning

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cutkosky20a.pdf(263.51 KB)
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Date
2020-07-13
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Authors
Cutkosky, Ashok
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OA Version
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Citation
Ashok Cutkosky. 2020. "Parameter-free, Dynamic, and Strongly-Adaptive Online Learning." International Conference on Machine Learning
Abstract
We provide a new online learning algorithm that for the first time combines several disparate notions of adaptivity. First, our algorithm obtains a “parameter-free” regret bound that adapts to the norm of the comparator and the squared norm of the size of the gradients it observes. Second, it obtains a “strongly-adaptive” regret bound, so that for any given interval of length N, the regret over the interval is Õ (√N). Finally, our algorithm obtains an optimal “dynamic” regret bound: for any sequence of comparators with path-length P, our algorithm obtains regret Õ (√𝑃𝑁) over intervals of length N. Our primary technique for achieving these goals is a new method of combining constrained online learning regret bounds that does not rely on an expert meta-algorithm to aggregate learners.
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Copyright © The authors and PMLR 2021. MLResearchPress.