Search Results for author: Patrick Rebeschini

Found 25 papers, 10 papers with code

Meta-learning the mirror map in policy mirror descent

no code implementations7 Feb 2024 Carlo Alfano, Sebastian Towers, Silvia Sapora, Chris Lu, Patrick Rebeschini

Policy Mirror Descent (PMD) is a popular framework in reinforcement learning, serving as a unifying perspective that encompasses numerous algorithms.

Meta-Learning

Generalization Bounds for Label Noise Stochastic Gradient Descent

no code implementations1 Nov 2023 Jung Eun Huh, Patrick Rebeschini

We develop generalization error bounds for stochastic gradient descent (SGD) with label noise in non-convex settings under uniform dissipativity and smoothness conditions.

Generalization Bounds

Sample-Efficiency in Multi-Batch Reinforcement Learning: The Need for Dimension-Dependent Adaptivity

no code implementations2 Oct 2023 Emmeran Johnson, Ciara Pike-Burke, Patrick Rebeschini

An algorithm is sample-efficient if it uses a number of queries $n$ to the environment that is polynomial in the dimension $d$ of the problem.

reinforcement-learning

A Novel Framework for Policy Mirror Descent with General Parameterization and Linear Convergence

1 code implementation NeurIPS 2023 Carlo Alfano, Rui Yuan, Patrick Rebeschini

Modern policy optimization methods in reinforcement learning, such as TRPO and PPO, owe their success to the use of parameterized policies.

Linear Convergence for Natural Policy Gradient with Log-linear Policy Parametrization

no code implementations30 Sep 2022 Carlo Alfano, Patrick Rebeschini

We analyze the convergence rate of the unregularized natural policy gradient algorithm with log-linear policy parametrizations in infinite-horizon discounted Markov decision processes.

Exponential Tail Local Rademacher Complexity Risk Bounds Without the Bernstein Condition

no code implementations23 Feb 2022 Varun Kanade, Patrick Rebeschini, Tomas Vaskevicius

Our main result is an exponential-tail excess risk bound expressed in terms of the offset Rademacher complexity that yields results at least as sharp as those obtainable via the classical theory.

Model Selection

Time-independent Generalization Bounds for SGLD in Non-convex Settings

no code implementations NeurIPS 2021 Tyler Farghly, Patrick Rebeschini

We establish generalization error bounds for stochastic gradient Langevin dynamics (SGLD) with constant learning rate under the assumptions of dissipativity and smoothness, a setting that has received increased attention in the sampling/optimization literature.

Generalization Bounds

On Optimal Interpolation In Linear Regression

1 code implementation NeurIPS 2021 Eduard Oravkin, Patrick Rebeschini

We identify a regime where the minimum-norm interpolator provably generalizes arbitrarily worse than the optimal response-linear achievable interpolator that we introduce, and validate with numerical experiments that the notion of optimality we consider can be achieved by interpolating methods that only use the training data as input in the case of an isotropic prior.

Learning Theory regression

Dimension-Free Rates for Natural Policy Gradient in Multi-Agent Reinforcement Learning

no code implementations23 Sep 2021 Carlo Alfano, Patrick Rebeschini

Cooperative multi-agent reinforcement learning is a decentralized paradigm in sequential decision making where agents distributed over a network iteratively collaborate with neighbors to maximize global (network-wide) notions of rewards.

Decision Making Multi-agent Reinforcement Learning +2

Comparing Classes of Estimators: When does Gradient Descent Beat Ridge Regression in Linear Models?

1 code implementation26 Aug 2021 Dominic Richards, Edgar Dobriban, Patrick Rebeschini

Methods for learning from data depend on various types of tuning parameters, such as penalization strength or step size.

regression Unity

Implicit Regularization in Matrix Sensing via Mirror Descent

1 code implementation NeurIPS 2021 Fan Wu, Patrick Rebeschini

We study discrete-time mirror descent applied to the unregularized empirical risk in matrix sensing.

Nearly Minimax-Optimal Rates for Noisy Sparse Phase Retrieval via Early-Stopped Mirror Descent

1 code implementation8 May 2021 Fan Wu, Patrick Rebeschini

This paper studies early-stopped mirror descent applied to noisy sparse phase retrieval, which is the problem of recovering a $k$-sparse signal $\mathbf{x}^\star\in\mathbb{R}^n$ from a set of quadratic Gaussian measurements corrupted by sub-exponential noise.

Retrieval

A Continuous-Time Mirror Descent Approach to Sparse Phase Retrieval

1 code implementation NeurIPS 2020 Fan Wu, Patrick Rebeschini

We analyze continuous-time mirror descent applied to sparse phase retrieval, which is the problem of recovering sparse signals from a set of magnitude-only measurements.

Retrieval

Decentralised Learning with Random Features and Distributed Gradient Descent

1 code implementation ICML 2020 Dominic Richards, Patrick Rebeschini, Lorenzo Rosasco

Under standard source and capacity assumptions, we establish high probability bounds on the predictive performance for each agent as a function of the step size, number of iterations, inverse spectral gap of the communication matrix and number of Random Features.

Hadamard Wirtinger Flow for Sparse Phase Retrieval

2 code implementations1 Jun 2020 Fan Wu, Patrick Rebeschini

We consider the problem of reconstructing an $n$-dimensional $k$-sparse signal from a set of noiseless magnitude-only measurements.

Retrieval

The Statistical Complexity of Early-Stopped Mirror Descent

no code implementations NeurIPS 2020 Tomas Vaškevičius, Varun Kanade, Patrick Rebeschini

Recently there has been a surge of interest in understanding implicit regularization properties of iterative gradient-based optimization algorithms.

Distributed Machine Learning with Sparse Heterogeneous Data

no code implementations NeurIPS 2021 Dominic Richards, Sahand N. Negahban, Patrick Rebeschini

Motivated by distributed machine learning settings such as Federated Learning, we consider the problem of fitting a statistical model across a distributed collection of heterogeneous data sets whose similarity structure is encoded by a graph topology.

BIG-bench Machine Learning Denoising +2

Implicit Regularization for Optimal Sparse Recovery

1 code implementation NeurIPS 2019 Tomas Vaškevičius, Varun Kanade, Patrick Rebeschini

We investigate implicit regularization schemes for gradient descent methods applied to unpenalized least squares regression to solve the problem of reconstructing a sparse signal from an underdetermined system of linear measurements under the restricted isometry assumption.

Computational Efficiency

Optimal Statistical Rates for Decentralised Non-Parametric Regression with Linear Speed-Up

no code implementations NeurIPS 2019 Dominic Richards, Patrick Rebeschini

We show that if agents hold sufficiently many samples with respect to the network size, then Distributed Gradient Descent achieves optimal statistical rates with a number of iterations that scales, up to a threshold, with the inverse of the spectral gap of the gossip matrix divided by the number of samples owned by each agent raised to a problem-dependent power.

regression

Decentralized Cooperative Stochastic Bandits

1 code implementation NeurIPS 2019 David Martínez-Rubio, Varun Kanade, Patrick Rebeschini

We design a fully decentralized algorithm that uses an accelerated consensus procedure to compute (delayed) estimates of the average of rewards obtained by all the agents for each arm, and then uses an upper confidence bound (UCB) algorithm that accounts for the delay and error of the estimates.

Multi-Armed Bandits

Graph-Dependent Implicit Regularisation for Distributed Stochastic Subgradient Descent

no code implementations18 Sep 2018 Dominic Richards, Patrick Rebeschini

We propose graph-dependent implicit regularisation strategies for distributed stochastic subgradient descent (Distributed SGD) for convex problems in multi-agent learning.

Accelerated consensus via Min-Sum Splitting

no code implementations NeurIPS 2017 Patrick Rebeschini, Sekhar C. Tatikonda

We apply the Min-Sum message-passing protocol to solve the consensus problem in distributed optimization.

Distributed Optimization

A New Approach to Laplacian Solvers and Flow Problems

no code implementations22 Nov 2016 Patrick Rebeschini, Sekhar Tatikonda

This paper investigates the behavior of the Min-Sum message passing scheme to solve systems of linear equations in the Laplacian matrices of graphs and to compute electric flows.

Scale-free network optimization: foundations and algorithms

no code implementations12 Feb 2016 Patrick Rebeschini, Sekhar Tatikonda

We propose a notion of correlation in constrained optimization that is based on the sensitivity of the optimal solution upon perturbations of the constraints.

Fast Mixing for Discrete Point Processes

no code implementations6 Jun 2015 Patrick Rebeschini, Amin Karbasi

We show that if the set function (not necessarily submodular) displays a natural notion of decay of correlation, then, for $\beta$ small enough, it is possible to design fast mixing Markov chain Monte Carlo methods that yield error bounds on marginal approximations that do not depend on the size of the set $V$.

Point Processes

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