no code implementations • 29 Sep 2023 • Steve Hanneke, Aryeh Kontorovich, Guy Kornowski
While the recent work of Hanneke et al. (2023) established tight uniform convergence bounds for average-smooth functions in the realizable case and provided a computationally efficient realizable learning algorithm, both of these results currently lack analogs in the general agnostic (i. e. noisy) case.
no code implementations • 10 Jul 2023 • Guy Kornowski, Ohad Shamir
Recent works proposed several stochastic zero-order algorithms that solve this task, all of which suffer from a dimension-dependence of $\Omega(d^{3/2})$ where $d$ is the dimension of the problem, which was conjectured to be optimal.
no code implementations • NeurIPS 2023 • Guy Kornowski, Gilad Yehudai, Ohad Shamir
Thus, we show that the input dimension has a crucial role on the type of overfitting in this setting, which we also validate empirically for intermediate dimensions.
no code implementations • 16 Feb 2023 • Michael I. Jordan, Guy Kornowski, Tianyi Lin, Ohad Shamir, Manolis Zampetakis
In particular, we prove a lower bound of $\Omega(d)$ for any deterministic algorithm.
no code implementations • 21 Sep 2022 • Guy Kornowski, Ohad Shamir
We study the oracle complexity of producing $(\delta,\epsilon)$-stationary points of Lipschitz functions, in the sense proposed by Zhang et al. [2020].
no code implementations • NeurIPS 2021 • Guy Kornowski, Ohad Shamir
For this approach, we prove under a mild assumption an inherent trade-off between oracle complexity and smoothness: On the one hand, smoothing a nonsmooth nonconvex function can be done very efficiently (e. g., by randomized smoothing), but with dimension-dependent factors in the smoothness parameter, which can strongly affect iteration complexity when plugging into standard smooth optimization methods.
no code implementations • 13 Oct 2020 • Guy Kornowski, Ohad Shamir
In this note, we consider the complexity of optimizing a highly smooth (Lipschitz $k$-th order derivative) and strongly convex function, via calls to a $k$-th order oracle which returns the value and first $k$ derivatives of the function at a given point, and where the dimension is unrestricted.