Dynamic Online Gradient Descent with Improved Query Complexity: A Theoretical Revisit
We provide a new theoretical analysis framework to investigate online gradient descent in the dynamic environment. Comparing with the previous work, the new framework recovers the state-of-the-art dynamic regret, but does not require extra gradient queries for every iteration. Specifically, when functions are $\alpha$ strongly convex and $\beta$ smooth, to achieve the state-of-the-art dynamic regret, the previous work requires $O(\kappa)$ with $\kappa = \frac{\beta}{\alpha}$ queries of gradients at every iteration. But, our framework shows that the query complexity can be improved to be $O(1)$, which does not depend on $\kappa$. The improvement is significant for ill-conditioned problems because that their objective function usually has a large $\kappa$.
Code (0)
등록된 구현이 없습니다.
Similar Papers 제목 키워드 기반
Improved Complexity for Smooth Nonconvex Optimization: A Two-Level Online Learning Approach with Quasi-Newton Methods
We study the problem of finding an $\epsilon$-first-order stationary point (FOSP) of a smooth function, given access only to gradient information. The best-known gradient query complexity for this task, assuming both the…
Unconstrained Online Optimization: Dynamic Regret Analysis of Strongly Convex and Smooth Problems
The regret bound of dynamic online learning algorithms is often expressed in terms of the variation in the function sequence ($V_T$) and/or the path-length of the minimizer sequence after $T$ rounds. For strongly convex …
Improved Analysis for Dynamic Regret of Strongly Convex and Smooth Functions
In this paper, we present an improved analysis for dynamic regret of strongly convex and smooth functions. Specifically, we investigate the Online Multiple Gradient Descent (OMGD) algorithm proposed by Zhang et al. (2017…
On the Dynamic Regret of Online Multiple Mirror Descent
We study the problem of online convex optimization, where a learner makes sequential decisions to minimize an accumulation of strongly convex costs over time. The quality of decisions is given in terms of the dynamic reg…
Adaptive Online Learning in Dynamic Environments
In this paper, we study online convex optimization in dynamic environments, and aim to bound the dynamic regret with respect to any sequence of comparators. Existing work have shown that online gradient descent enjoys an…