arXiv research

Stochastic proximal point algorithm with momentum converges faster and is more stable than standard methods.

Develops a new SPP algorithm with variance reduction for weakly convex optimization.

New method reduces variance in stochastic optimization with high confidence.

The paper tackles finding stationary points in stochastic convex optimization problems.

Large sectors of the recent optimization literature focused in the last decade on the development of optimal stochastic first order schemes for constrained convex models under progressively relaxed assumptions. Stochastic proximal point is an iterative scheme born from the adaptation of proximal point algorithm to nois…

PDNS tackles multimodal sampling challenges using proximal point method.

A method for estimating the median of gradients in stochastic optimization.

We develop model-based methods for solving stochastic convex optimization problems, introducing the approximate-proximal point, or aProx, family, which includes stochastic subgradient, proximal point, and bundle methods. When the modeling approaches we propose are appropriately accurate, the methods enjoy stronger conv…

New algorithms accelerate model-based optimization for stochastic problems.

Two new algorithms improve federated optimization under second-order similarity.

We consider saddle point problems which objective functions are the average of $n$ strongly convex-concave individual components. Recently, researchers exploit variance reduction methods to solve such problems and achieve linear-convergence guarantees. However, these methods have a slow convergence when the condition n…

Improves RL algorithms with two techniques.

We analyze stochastic algorithms for optimizing nonconvex, nonsmooth finite-sum problems, where the nonconvex part is smooth and the nonsmooth part is convex. Surprisingly, unlike the smooth case, our knowledge of this fundamental problem is very limited. For example, it is not known whether the proximal stochastic gra…

Two new methods solve nonsmooth optimization on Riemannian Stiefel manifold.

In this paper, a novel stochastic extra-step quasi-Newton method is developed to solve a class of nonsmooth nonconvex composite optimization problems. We assume that the gradient of the smooth part of the objective function can only be approximated by stochastic oracles. The proposed method combines general stochastic …

APO optimizes neural network parameters by amortizing proximal point methods.

A new method solves l1-regularized optimization problems efficiently and sparsely.

Stochastic version of proximal distance algorithm analyzed and validated.

We develop a family of accelerated stochastic algorithms that minimize sums of convex functions. Our algorithms improve upon the fastest running time for empirical risk minimization (ERM), and in particular linear least-squares regression, across a wide range of problem settings. To achieve this, we establish a framewo…

Here we study non-convex composite optimization: first, a finite-sum of smooth but non-convex functions, and second, a general function that admits a simple proximal mapping. Most research on stochastic methods for composite optimization assumes convexity or strong convexity of each function. In this paper, we extend t…

Paper introduces a new reinforcement learning method with improved performance.

New method improves convergence of SPP for convex optimization problems.

Two algorithms find optimal points in decentralized optimization.

New method solves complex optimization problems with reduced sample complexity.

Unified framework for training neural networks with non-smooth, non-convex regularizers.

The need for parameter estimation with massive datasets has reinvigorated interest in stochastic optimization and iterative estimation procedures. Stochastic approximations are at the forefront of this recent development as they yield procedures that are simple, general, and fast. However, standard stochastic approxima…

We consider the problem of minimizing the sum of two convex functions: one is the average of a large number of smooth component functions, and the other is a general convex function that admits a simple proximal mapping. We assume the whole objective function is strongly convex. Such problems often arise in machine lea…

New methods help escape strict saddle points in nonsmooth optimization.

In this paper we study several classes of stochastic optimization algorithms enriched with heavy ball momentum. Among the methods studied are: stochastic gradient descent, stochastic Newton, stochastic proximal point and stochastic dual subspace ascent. This is the first time momentum variants of several of these metho…

Large models are prevalent in modern machine learning scenarios, including deep learning, recommender systems, etc., which can have millions or even billions of parameters. Parallel algorithms have become an essential solution technique to many large-scale machine learning jobs. In this paper, we propose a model parall…

SMP model preserves proximity and permutation in graph neural networks.

Optimizes convergence rate of stochastic proximal algorithms for composite convex problems.

Develops minibatch stochastic proximal gradient for large-scale learning models.

Nonconvex and nonsmooth problems have recently attracted considerable attention in machine learning. However, developing efficient methods for the nonconvex and nonsmooth optimization problems with certain performance guarantee remains a challenge. Proximal coordinate descent (PCD) has been widely used for solving opti…

The paper analyzes two ISGD modes for statistical inference, deriving error bounds and confidence intervals.

Proposes a semi-implicit back propagation method for neural networks.

We propose a new algorithm---Stochastic Proximal Langevin Algorithm (SPLA)---for sampling from a log concave distribution. Our method is a generalization of the Langevin algorithm to potentials expressed as the sum of one stochastic smooth term and multiple stochastic nonsmooth terms. In each iteration, our splitting t…

Wasserstein distance plays increasingly important roles in machine learning, stochastic programming and image processing. Major efforts have been under way to address its high computational complexity, some leading to approximate or regularized variations such as Sinkhorn distance. However, as we will demonstrate, regu…

The paper tackles counterfactual learning for stochastic policies with continuous actions.

Sampling without replacement speeds up optimization in minimax problems.

New algorithms tackle machine learning problems using manifold proximal point methods.

We propose an inexact variable-metric proximal point algorithm to accelerate gradient-based optimization algorithms. The proposed scheme, called QNing can be notably applied to incremental first-order methods such as the stochastic variance-reduced gradient descent algorithm (SVRG) and other randomized incremental opti…

In this paper, we discuss the problem of minimizing the sum of two convex functions: a smooth function plus a non-smooth function. Further, the smooth part can be expressed by the average of a large number of smooth component functions, and the non-smooth part is equipped with a simple proximal mapping. We propose a pr…

Improves time series classification with forest proximities.

New algorithm speeds up sampling from complex distributions.

Proximal gradient method has been playing an important role to solve many machine learning tasks, especially for the nonsmooth problems. However, in some machine learning problems such as the bandit model and the black-box learning problem, proximal gradient method could fail because the explicit gradients of these pro…

Clarifies when solutions to stochastic PDEs stay near given subsets.

Two new algorithms solve privacy-constrained SVI and SSP problems.