In this work we consider the stochastic minimization of nonsmooth convex loss functions, a central problem in machine learning. We propose a novel algorithm called Accelerated Nonsmooth Stochastic Gradient Descent (ANSGD), which exploits the structure of common nonsmooth loss functions to achieve optimal convergence ra…
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New theory for nonsmooth systems helps optimize and control complex functions.
PPGD solves nonconvex nonsmooth optimization problems without KL property.
Study compares nonsmooth spaces with integrable Ricci bounds.
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…
Regularity results for geodesic X-ray transform on nonsmooth manifolds
Paper develops algorithms for nonsmooth, nonconvex statistical learning problems.
New Langevin Monte Carlo algorithms for sampling from nonsmooth distributions.
We consider a class of nonconvex nonsmooth optimization problems whose objective is the sum of a smooth function and a finite number of nonnegative proper closed possibly nonsmooth functions (whose proximal mappings are easy to compute), some of which are further composed with linear maps. This kind of problems arises …
New methods help escape strict saddle points in nonsmooth optimization.
We present a stochastic setting for optimization problems with nonsmooth convex separable objective functions over linear equality constraints. To solve such problems, we propose a stochastic Alternating Direction Method of Multipliers (ADMM) algorithm. Our algorithm applies to a more general class of nonsmooth convex …
The paper guarantees global stability for stochastic subgradient methods in nonsmooth nonconvex optimization.
Paper develops privacy-preserving federated learning for nonsmooth objectives.
Improved shuffling gradient methods converge faster for nonsmooth convex optimization.
Develops a mathematical model for automatic differentiation in machine learning.
Two new methods solve nonsmooth optimization on Riemannian Stiefel manifold.
We consider in this paper a class of composite optimization problems whose objective function is given by the summation of a general smooth and nonsmooth component, together with a relatively simple nonsmooth term. We present a new class of first-order methods, namely the gradient sliding algorithms, which can skip the…
In this paper, we consider the problem of minimizing the average of a large number of nonsmooth and convex functions. Such problems often arise in typical machine learning problems as empirical risk minimization, but are computationally very challenging. We develop and analyze a new algorithm that achieves robust linea…
New method solves nonsmooth low-rank matrix optimization problems efficiently.
New algorithm for fast nonsmooth optimization with applications in image processing and machine learning.
Frank-Wolfe methods (FW) have gained significant interest in the machine learning community due to its ability to efficiently solve large problems that admit a sparse structure (e.g. sparse vectors and low-rank matrices). However the performance of the existing FW method hinges on the quality of the linear approximatio…
Study on numerical reliability of AD for MaxPool in neural nets.
We introduce a proximal subdifferential and develop a calculus for nonsmooth functions defined on any Riemannian manifold . We give several applications of this theory, concerning: 1) differentiability and geometrical properties of the distance function to a closed subset of ; 2) solvability and implicit func…
Many machine learning techniques sacrifice convenient computational structures to gain estimation robustness and modeling flexibility. However, by exploring the modeling structures, we find these "sacrifices" do not always require more computational efforts. To shed light on such a "free-lunch" phenomenon, we study the…
This paper concerns dictionary learning, i.e., sparse coding, a fundamental representation learning problem. We show that a subgradient descent algorithm, with random initialization, can provably recover orthogonal dictionaries on a natural nonsmooth, nonconvex minimization formulation of the problem, under mi…
We study the dual formulation of the utility maximization problem in incomplete markets when the utility function is finitely valued on the whole real line. We extend the existing results in this literature in two directions. First, we allow for nonsmooth utility functions, so as to include the shortfall minimization p…
Unified Lagrangian-based methods for nonsmooth nonconvex optimization.
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…
Study on Adam-family methods for nonsmooth optimization with convergence guarantees.
This paper tackles nonsmooth optimization in machine learning.
In this paper, we consider the convergence of an abstract inexact nonconvex and nonsmooth algorithm. We promise a pseudo sufficient descent condition and a pseudo relative error condition, which are both related to an auxiliary sequence, for the algorithm; and a continuity condition is assumed to hold. In fact, a lot o…
Study on nonsmooth contractive SA with constant stepsize and Q-learning.
We maximize the expected utility of terminal wealth in an incomplete market where there are cone constraints on the investor's portfolio process and the utility function is not assumed to be strictly concave or differentiable. We establish the existence of the optimal solutions to the primal and dual problems and their…
Much of the vast literature on the integral during the last two centuries concerns extending the class of integrable functions. In contrast, our viewpoint is akin to that taken by Hassler Whitney [{\it Geometric integration theory}, Princeton Univ. Press, Princeton, NJ, 1957] and by geometric measure theorists because …
New stability bounds for SGD on nonsmooth convex losses.
Paper tackles efficient SVM classification over decentralized networks.
Improved method reduces projection calls for nonsmooth convex optimization.
New adaptive methods solve weakly convex stochastic optimization problems.
Cyclic coordinate descent identifies models in finite time and converges linearly.
The paper relaxes assumptions for analyzing stochastic optimization algorithms.
A new method solves convex optimization problems on manifolds efficiently.
Proposes BMME for optimizing nonsmooth nonconvex problems with block structure.
Develops a fast algorithm for high-dimensional LASSO penalized quantile regression.
We consider optimization problems over the Stiefel manifold whose objective function is the summation of a smooth function and a nonsmooth function. Existing methods for solving this kind of problems can be classified into three classes. Algorithms in the first class rely on information of the subgradients of the objec…
We construct some nonsmoothable actions of Z2 * Z2 on spin four-manifolds by using an equivariant version of Furuta' s 10/8inequality. The examples satisfy following property: any proper subgroup of Z2 * Z2 is smoothable for some smooth structure.
In regularized risk minimization, the associated optimization problem becomes particularly difficult when both the loss and regularizer are nonsmooth. Existing approaches either have slow or unclear convergence properties, are restricted to limited problem subclasses, or require careful setting of a smoothing parameter…
We construct a nonsmoothable Z\times Z-action on the connected sum of an Enriques surface and S^2\times S^2, such that each of generators is smoothable. We also construct a nonsmoothable self-homeomorphism on an Enriques surface.
As surrogate functions of -norm, many nonconvex penalty functions have been proposed to enhance the sparse vector recovery. It is easy to extend these nonconvex penalty functions on singular values of a matrix to enhance low-rank matrix recovery. However, different from convex optimization, solving the nonconvex l…