Search Results for author: Alexander Gasnikov

Found 61 papers, 18 papers with code

Optimal Flow Matching: Learning Straight Trajectories in Just One Step

no code implementations19 Mar 2024 Nikita Kornilov, Alexander Gasnikov, Alexander Korotin

Over the several recent years, there has been a boom in development of flow matching methods for generative modeling.

AdaBatchGrad: Combining Adaptive Batch Size and Adaptive Step Size

no code implementations7 Feb 2024 Petr Ostroukhov, Aigerim Zhumabayeva, Chulu Xiang, Alexander Gasnikov, Martin Takáč, Dmitry Kamzolov

To substantiate the efficacy of our method, we experimentally show, how the introduction of adaptive step size and adaptive batch size gradually improves the performance of regular SGD.

Activations and Gradients Compression for Model-Parallel Training

1 code implementation15 Jan 2024 Mikhail Rudakov, Aleksandr Beznosikov, Yaroslav Kholodov, Alexander Gasnikov

We analyze compression methods such as quantization and TopK compression, and also experiment with error compensation techniques.

Image Classification Language Modelling +1

Implicitly normalized forecaster with clipping for linear and non-linear heavy-tailed multi-armed bandits

1 code implementation11 May 2023 Yuriy Dorn, Nikita Kornilov, Nikolay Kutuzov, Alexander Nazin, Eduard Gorbunov, Alexander Gasnikov

We establish convergence results under mild assumptions on the rewards distribution and demonstrate that INF-clip is optimal for linear heavy-tailed stochastic MAB problems and works well for non-linear ones.

Multi-Armed Bandits

Similarity, Compression and Local Steps: Three Pillars of Efficient Communications for Distributed Variational Inequalities

no code implementations NeurIPS 2023 Aleksandr Beznosikov, Martin Takáč, Alexander Gasnikov

The methods presented in this paper have the best theoretical guarantees of communication complexity and are significantly ahead of other methods for distributed variational inequalities.

Distributed Computing

An Optimal Algorithm for Strongly Convex Min-min Optimization

no code implementations29 Dec 2022 Alexander Gasnikov, Dmitry Kovalev, Grigory Malinovsky

In this paper we study the smooth strongly convex minimization problem $\min_{x}\min_y f(x, y)$.

SARAH-based Variance-reduced Algorithm for Stochastic Finite-sum Cocoercive Variational Inequalities

no code implementations12 Oct 2022 Aleksandr Beznosikov, Alexander Gasnikov

In this paper we consider the problem of stochastic finite-sum cocoercive variational inequalities.

Smooth Monotone Stochastic Variational Inequalities and Saddle Point Problems: A Survey

no code implementations29 Aug 2022 Aleksandr Beznosikov, Boris Polyak, Eduard Gorbunov, Dmitry Kovalev, Alexander Gasnikov

This paper is a survey of methods for solving smooth (strongly) monotone stochastic variational inequalities.

On Scaled Methods for Saddle Point Problems

no code implementations16 Jun 2022 Aleksandr Beznosikov, Aibek Alanov, Dmitry Kovalev, Martin Takáč, Alexander Gasnikov

Methods with adaptive scaling of different features play a key role in solving saddle point problems, primarily due to Adam's popularity for solving adversarial machine learning problems, including GANS training.

Clipped Stochastic Methods for Variational Inequalities with Heavy-Tailed Noise

1 code implementation2 Jun 2022 Eduard Gorbunov, Marina Danilova, David Dobre, Pavel Dvurechensky, Alexander Gasnikov, Gauthier Gidel

In this work, we prove the first high-probability complexity results with logarithmic dependence on the confidence level for stochastic methods for solving monotone and structured non-monotone VIPs with non-sub-Gaussian (heavy-tailed) noise and unbounded domains.

Optimal Gradient Sliding and its Application to Distributed Optimization Under Similarity

no code implementations30 May 2022 Dmitry Kovalev, Aleksandr Beznosikov, Ekaterina Borodich, Alexander Gasnikov, Gesualdo Scutari

Finally the method is extended to distributed saddle-problems (under function similarity) by means of solving a class of variational inequalities, achieving lower communication and computation complexity bounds.

Distributed Optimization

The First Optimal Acceleration of High-Order Methods in Smooth Convex Optimization

1 code implementation19 May 2022 Dmitry Kovalev, Alexander Gasnikov

Arjevani et al. (2019) established the lower bound $\Omega\left(\epsilon^{-2/(3p+1)}\right)$ on the number of the $p$-th order oracle calls required by an algorithm to find an $\epsilon$-accurate solution to the problem, where the $p$-th order oracle stands for the computation of the objective function value and the derivatives up to the order $p$.

Open-Ended Question Answering

The First Optimal Algorithm for Smooth and Strongly-Convex-Strongly-Concave Minimax Optimization

no code implementations11 May 2022 Dmitry Kovalev, Alexander Gasnikov

However, the existing state-of-the-art methods do not match this lower bound: algorithms of Lin et al. (2020) and Wang and Li (2020) have gradient evaluation complexity $\mathcal{O}\left( \sqrt{\kappa_x\kappa_y}\log^3\frac{1}{\epsilon}\right)$ and $\mathcal{O}\left( \sqrt{\kappa_x\kappa_y}\log^3 (\kappa_x\kappa_y)\log\frac{1}{\epsilon}\right)$, respectively.

Optimal Algorithms for Decentralized Stochastic Variational Inequalities

no code implementations6 Feb 2022 Dmitry Kovalev, Aleksandr Beznosikov, Abdurakhmon Sadiev, Michael Persiianov, Peter Richtárik, Alexander Gasnikov

Our algorithms are the best among the available literature not only in the decentralized stochastic case, but also in the decentralized deterministic and non-distributed stochastic cases.

Accelerated Primal-Dual Gradient Method for Smooth and Convex-Concave Saddle-Point Problems with Bilinear Coupling

no code implementations30 Dec 2021 Dmitry Kovalev, Alexander Gasnikov, Peter Richtárik

In this paper we study the convex-concave saddle-point problem $\min_x \max_y f(x) + y^T \mathbf{A} x - g(y)$, where $f(x)$ and $g(y)$ are smooth and convex functions.

Lower Bounds and Optimal Algorithms for Smooth and Strongly Convex Decentralized Optimization Over Time-Varying Networks

no code implementations NeurIPS 2021 Dmitry Kovalev, Elnur Gasanov, Alexander Gasnikov, Peter Richtarik

We consider the task of minimizing the sum of smooth and strongly convex functions stored in a decentralized manner across the nodes of a communication network whose links are allowed to change in time.

Distributed Saddle-Point Problems Under Data Similarity

no code implementations NeurIPS 2021 Aleksandr Beznosikov, Gesualdo Scutari, Alexander Rogozin, Alexander Gasnikov

We study solution methods for (strongly-)convex-(strongly)-concave Saddle-Point Problems (SPPs) over networks of two type--master/workers (thus centralized) architectures and mesh (thus decentralized) networks.

Acceleration in Distributed Optimization under Similarity

no code implementations24 Oct 2021 Ye Tian, Gesualdo Scutari, Tianyu Cao, Alexander Gasnikov

In order to reduce the number of communications to reach a solution accuracy, we proposed a {\it preconditioned, accelerated} distributed method.

Distributed Optimization

Distributed Methods with Compressed Communication for Solving Variational Inequalities, with Theoretical Guarantees

no code implementations7 Oct 2021 Aleksandr Beznosikov, Peter Richtárik, Michael Diskin, Max Ryabinin, Alexander Gasnikov

Due to these considerations, it is important to equip existing methods with strategies that would allow to reduce the volume of transmitted information during training while obtaining a model of comparable quality.

Distributed Computing Federated Learning

Distributed Saddle-Point Problems Under Similarity

1 code implementation22 Jul 2021 Aleksandr Beznosikov, Gesualdo Scutari, Alexander Rogozin, Alexander Gasnikov

We study solution methods for (strongly-)convex-(strongly)-concave Saddle-Point Problems (SPPs) over networks of two type - master/workers (thus centralized) architectures and meshed (thus decentralized) networks.

Decentralized Local Stochastic Extra-Gradient for Variational Inequalities

no code implementations15 Jun 2021 Aleksandr Beznosikov, Pavel Dvurechensky, Anastasia Koloskova, Valentin Samokhin, Sebastian U Stich, Alexander Gasnikov

We extend the stochastic extragradient method to this very general setting and theoretically analyze its convergence rate in the strongly-monotone, monotone, and non-monotone (when a Minty solution exists) settings.

Federated Learning

Decentralized Personalized Federated Learning for Min-Max Problems

no code implementations14 Jun 2021 Ekaterina Borodich, Aleksandr Beznosikov, Abdurakhmon Sadiev, Vadim Sushko, Nikolay Savelyev, Martin Takáč, Alexander Gasnikov

Personalized Federated Learning (PFL) has witnessed remarkable advancements, enabling the development of innovative machine learning applications that preserve the privacy of training data.

Distributed Optimization Personalized Federated Learning

Near-Optimal High Probability Complexity Bounds for Non-Smooth Stochastic Optimization with Heavy-Tailed Noise

1 code implementation10 Jun 2021 Eduard Gorbunov, Marina Danilova, Innokentiy Shibaev, Pavel Dvurechensky, Alexander Gasnikov

In our paper, we resolve this issue and derive the first high-probability convergence results with logarithmic dependence on the confidence level for non-smooth convex stochastic optimization problems with non-sub-Gaussian (heavy-tailed) noise.

Stochastic Optimization

Gradient Clipping Helps in Non-Smooth Stochastic Optimization with Heavy-Tailed Noise

no code implementations NeurIPS 2021 Eduard Gorbunov, Marina Danilova, Innokentiy Andreevich Shibaev, Pavel Dvurechensky, Alexander Gasnikov

In our paper, we resolve this issue and derive the first high-probability convergence results with logarithmical dependence on the confidence level for non-smooth convex stochastic optimization problems with non-sub-Gaussian (heavy-tailed) noise.

Stochastic Optimization

Primal-Dual Stochastic Mirror Descent for MDPs

no code implementations27 Feb 2021 Daniil Tiapkin, Alexander Gasnikov

We consider the problem of learning the optimal policy for infinite-horizon Markov decision processes (MDPs).

ADOM: Accelerated Decentralized Optimization Method for Time-Varying Networks

no code implementations18 Feb 2021 Dmitry Kovalev, Egor Shulgin, Peter Richtárik, Alexander Rogozin, Alexander Gasnikov

We propose ADOM - an accelerated method for smooth and strongly convex decentralized optimization over time-varying networks.

Decentralized Distributed Optimization for Saddle Point Problems

no code implementations15 Feb 2021 Alexander Rogozin, Alexander Beznosikov, Darina Dvinskikh, Dmitry Kovalev, Pavel Dvurechensky, Alexander Gasnikov

We consider distributed convex-concave saddle point problems over arbitrary connected undirected networks and propose a decentralized distributed algorithm for their solution.

Distributed Optimization Optimization and Control Distributed, Parallel, and Cluster Computing

Flexible Modification of Gauss-Newton Method and Its Stochastic Extension

no code implementations1 Feb 2021 Nikita Yudin, Alexander Gasnikov

This work presents a novel version of recently developed Gauss-Newton method for solving systems of nonlinear equations, based on upper bound of solution residual and quadratic regularization ideas.

Stochastic Optimization Optimization and Control

Improved Exploiting Higher Order Smoothness in Derivative-free Optimization and Continuous Bandit

no code implementations11 Jan 2021 Vasilii Novitskii, Alexander Gasnikov

We consider $\beta$-smooth (satisfies the generalized Holder condition with parameter $\beta > 2$) stochastic convex optimization problem with zero-order one-point oracle.

Optimization and Control

Tensor methods for strongly convex strongly concave saddle point problems and strongly monotone variational inequalities

no code implementations31 Dec 2020 Petr Ostroukhov, Rinat Kamalov, Pavel Dvurechensky, Alexander Gasnikov

The first method is based on the assumption of $p$-th order smoothness of the objective and it achieves a convergence rate of $O \left( \left( \frac{L_p R^{p - 1}}{\mu} \right)^\frac{2}{p + 1} \log \frac{\mu R^2}{\varepsilon_G} \right)$, where $R$ is an estimate of the initial distance to the solution, and $\varepsilon_G$ is the error in terms of duality gap.

Optimization and Control

Inexact Tensor Methods and Their Application to Stochastic Convex Optimization

no code implementations31 Dec 2020 Artem Agafonov, Dmitry Kamzolov, Pavel Dvurechensky, Alexander Gasnikov

We propose general non-accelerated and accelerated tensor methods under inexact information on the derivatives of the objective, analyze their convergence rate.

Optimization and Control

Recent Theoretical Advances in Non-Convex Optimization

no code implementations11 Dec 2020 Marina Danilova, Pavel Dvurechensky, Alexander Gasnikov, Eduard Gorbunov, Sergey Guminov, Dmitry Kamzolov, Innokentiy Shibaev

For this setting, we first present known results for the convergence rates of deterministic first-order methods, which are then followed by a general theoretical analysis of optimal stochastic and randomized gradient schemes, and an overview of the stochastic first-order methods.

Finding equilibrium in two-stage traffic assignment model

no code implementations8 Dec 2020 Ekaterina Kotliarova, Alexander Gasnikov, Evgenia Gasnikova

The first block consists of model for calculating correspondence (demand) matrix, whereas the second block is a traffic assignment model.

Optimization and Control

Zeroth-Order Algorithms for Smooth Saddle-Point Problems

no code implementations21 Sep 2020 Abdurakhmon Sadiev, Aleksandr Beznosikov, Pavel Dvurechensky, Alexander Gasnikov

In particular, our analysis shows that in the case when the feasible set is a direct product of two simplices, our convergence rate for the stochastic term is only by a $\log n$ factor worse than for the first-order methods.

Finding Equilibria in the Traffic Assignment Problem with Primal-Dual Gradient Methods for Stable Dynamics Model and Beckmann Model

1 code implementation6 Aug 2020 Meruza Kubentayeva, Alexander Gasnikov

In this paper we consider the application of several gradient methods to the traffic assignment problem: we search equilibria in the stable dynamics model (Nesterov and De Palma, 2003) and the Beckmann model.

Optimization and Control

Stochastic Saddle-Point Optimization for Wasserstein Barycenters

no code implementations11 Jun 2020 Daniil Tiapkin, Alexander Gasnikov, Pavel Dvurechensky

This leads to a complicated stochastic optimization problem where the objective is given as an expectation of a function given as a solution to a random optimization problem.

Stochastic Optimization

Stochastic Optimization with Heavy-Tailed Noise via Accelerated Gradient Clipping

1 code implementation NeurIPS 2020 Eduard Gorbunov, Marina Danilova, Alexander Gasnikov

In this paper, we propose a new accelerated stochastic first-order method called clipped-SSTM for smooth convex stochastic optimization with heavy-tailed distributed noise in stochastic gradients and derive the first high-probability complexity bounds for this method closing the gap in the theory of stochastic optimization with heavy-tailed noise.

Stochastic Optimization

Gradient-Free Methods for Saddle-Point Problem

no code implementations12 May 2020 Aleksandr Beznosikov, Abdurakhmon Sadiev, Alexander Gasnikov

In the second part of the paper, we analyze the case when such an assumption cannot be made, we propose a general approach on how to modernize the method to solve this problem, and also we apply this approach to particular cases of some classical sets.

Accelerated meta-algorithm for convex optimization

2 code implementations18 Apr 2020 Darina Dvinskikh, Dmitry Kamzolov, Alexander Gasnikov, Pavel Dvurechensky, Dmitry Pasechnyk, Vladislav Matykhin, Alexei Chernov

We propose an accelerated meta-algorithm, which allows to obtain accelerated methods for convex unconstrained minimization in different settings.

Optimization and Control

Adaptive Catalyst for Smooth Convex Optimization

1 code implementation25 Nov 2019 Anastasiya Ivanova, Dmitry Pasechnyuk, Dmitry Grishchenko, Egor Shulgin, Alexander Gasnikov, Vladislav Matyukhin

In this paper, we present a generic framework that allows accelerating almost arbitrary non-accelerated deterministic and randomized algorithms for smooth convex optimization problems.

Optimization and Control

Adaptive Gradient Descent for Convex and Non-Convex Stochastic Optimization

1 code implementation19 Nov 2019 Aleksandr Ogaltsov, Darina Dvinskikh, Pavel Dvurechensky, Alexander Gasnikov, Vladimir Spokoiny

In this paper we propose several adaptive gradient methods for stochastic optimization.

Optimization and Control

On a Combination of Alternating Minimization and Nesterov's Momentum

no code implementations9 Jun 2019 Sergey Guminov, Pavel Dvurechensky, Nazarii Tupitsa, Alexander Gasnikov

In this paper we combine AM and Nesterov's acceleration to propose an accelerated alternating minimization algorithm.

A Dual Approach for Optimal Algorithms in Distributed Optimization over Networks

no code implementations3 Sep 2018 César A. Uribe, Soomin Lee, Alexander Gasnikov, Angelia Nedić

Then, we study distributed optimization algorithms for non-dual friendly functions, as well as a method to improve the dependency on the parameters of the functions involved.

Distributed Optimization

On the upper bound for the mathematical expectation of the norm of a vector uniformly distributed on the sphere and the phenomenon of concentration of uniform measure on the sphere

2 code implementations10 Apr 2018 Eduard Gorbunov, Evgeniya Vorontsova, Alexander Gasnikov

We considered the problem of obtaining upper bounds for the mathematical expectation of the $q$-norm ($2\leqslant q \leqslant \infty$) of the vector which is uniformly distributed on the unit Euclidean sphere.

Optimization and Control

Distributed Computation of Wasserstein Barycenters over Networks

no code implementations8 Mar 2018 César A. Uribe, Darina Dvinskikh, Pavel Dvurechensky, Alexander Gasnikov, Angelia Nedić

We propose a new \cu{class-optimal} algorithm for the distributed computation of Wasserstein Barycenters over networks.

An Accelerated Method for Derivative-Free Smooth Stochastic Convex Optimization

1 code implementation25 Feb 2018 Eduard Gorbunov, Pavel Dvurechensky, Alexander Gasnikov

In the two-point feedback setting, i. e. when pairs of function values are available, we propose an accelerated derivative-free algorithm together with its complexity analysis.

Optimization and Control Computational Complexity

Computational Optimal Transport: Complexity by Accelerated Gradient Descent Is Better Than by Sinkhorn's Algorithm

1 code implementation ICML 2018 Pavel Dvurechensky, Alexander Gasnikov, Alexey Kroshnin

We analyze two algorithms for approximating the general optimal transport (OT) distance between two discrete distributions of size $n$, up to accuracy $\varepsilon$.

Data Structures and Algorithms Optimization and Control

Optimal Algorithms for Distributed Optimization

no code implementations1 Dec 2017 César A. Uribe, Soomin Lee, Alexander Gasnikov, Angelia Nedić

In this paper, we study the optimal convergence rate for distributed convex optimization problems in networks.

Distributed Optimization

Accelerated Directional Search with non-Euclidean prox-structure

2 code implementations30 Sep 2017 Evgeniya Vorontsova, Alexander Gasnikov, Eduard Gorbunov

In the paper we show how to make Nesterov's method $n$-times faster (up to a $\log n$-factor) in this case.

Optimization and Control

Learning Supervised PageRank with Gradient-Based and Gradient-Free Optimization Methods

no code implementations NeurIPS 2016 Lev Bogolubsky, Pavel Dvurechenskii, Alexander Gasnikov, Gleb Gusev, Yurii Nesterov, Andrei M. Raigorodskii, Aleksey Tikhonov, Maksim Zhukovskii

In this paper, we consider a non-convex loss-minimization problem of learning Supervised PageRank models, which can account for features of nodes and edges.

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