Search Results for author: Kfir Levy

Found 11 papers, 1 papers with code

Online Convex Optimization in the Random Order Model

no code implementations ICML 2020 Dan Garber, Gal Korcia, Kfir Levy

Focusing on two important families of online tasks, one which generalizes online linear and logistic regression, and the other being online PCA, we show that under standard well-conditioned-data assumptions (that are often being made in the corresponding offline settings), standard online gradient descent (OGD) methods become much more efficient in the random-order model.

regression

Solving Non-Rectangular Reward-Robust MDPs via Frequency Regularization

no code implementations3 Sep 2023 Uri Gadot, Esther Derman, Navdeep Kumar, Maxence Mohamed Elfatihi, Kfir Levy, Shie Mannor

In robust Markov decision processes (RMDPs), it is assumed that the reward and the transition dynamics lie in a given uncertainty set.

Bring Your Own (Non-Robust) Algorithm to Solve Robust MDPs by Estimating The Worst Kernel

no code implementations9 Jun 2023 Kaixin Wang, Uri Gadot, Navdeep Kumar, Kfir Levy, Shie Mannor

Robust Markov Decision Processes (RMDPs) provide a framework for sequential decision-making that is robust to perturbations on the transition kernel.

Decision Making reinforcement-learning +2

An Efficient Solution to s-Rectangular Robust Markov Decision Processes

no code implementations31 Jan 2023 Navdeep Kumar, Kfir Levy, Kaixin Wang, Shie Mannor

We present an efficient robust value iteration for \texttt{s}-rectangular robust Markov Decision Processes (MDPs) with a time complexity comparable to standard (non-robust) MDPs which is significantly faster than any existing method.

LEMMA

Policy Gradient for Reinforcement Learning with General Utilities

no code implementations3 Oct 2022 Navdeep Kumar, Kaixin Wang, Kfir Levy, Shie Mannor

The policy gradient theorem proves to be a cornerstone in Linear RL due to its elegance and ease of implementability.

reinforcement-learning Reinforcement Learning +1

Efficient Policy Iteration for Robust Markov Decision Processes via Regularization

1 code implementation28 May 2022 Navdeep Kumar, Kfir Levy, Kaixin Wang, Shie Mannor

But we don't have a clear understanding to exploit this equivalence, to do policy improvement steps to get the optimal value function or policy.

STORM+: Fully Adaptive SGD with Recursive Momentum for Nonconvex Optimization

no code implementations NeurIPS 2021 Kfir Levy, Ali Kavis, Volkan Cevher

In this work we propose $\rm{STORM}^{+}$, a new method that is completely parameter-free, does not require large batch-sizes, and obtains the optimal $O(1/T^{1/3})$ rate for finding an approximate stationary point.

Online to Offline Conversions, Universality and Adaptive Minibatch Sizes

no code implementations NeurIPS 2017 Kfir Levy

We present an approach towards convex optimization that relies on a novel scheme which converts adaptive online algorithms into offline methods.

Fast Rates for Exp-concave Empirical Risk Minimization

no code implementations NeurIPS 2015 Tomer Koren, Kfir Levy

In this setting, we establish the first evidence that ERM is able to attain fast generalization rates, and show that the expected loss of the ERM solution in $d$ dimensions converges to the optimal expected loss in a rate of $d/n$.

regression Stochastic Optimization

Bandit Convex Optimization: Towards Tight Bounds

no code implementations NeurIPS 2014 Elad Hazan, Kfir Levy

Bandit Convex Optimization (BCO) is a fundamental framework for decision making under uncertainty, which generalizes many problems from the realm of online and statistical learning.

Decision Making Decision Making Under Uncertainty +1

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