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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,694 papers · 148 categories

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219437656874 · Jun 202019922001200920172026
48 results for SARAH algorithm

StochAstic Recursive grAdient algoritHm (SARAH), originally proposed for convex optimization and also proven to be effective for general nonconvex optimization, has received great attention due to its simple recursive framework for updating stochastic gradient estimates. The performance of SARAH significantly depends o…

2019-06-20abs ↗pdf ↗

Paper develops probabilistic bounds for a stochastic gradient algorithm in non-convex problems.

problem Stochastic optimization in non-convex finite sum problems.
method Develops a new dimension-free Azuma-Hoeffding type bound for a martingale difference sequence.
result Empirical results show superior probabilistic performance of Prob-SARAH compared to other algorithms.

GT-SARAH optimizes decentralized non-convex problems with recursive variance reduction.

problem Decentralized non-convex optimization of NN functions over a network.
method Stochastic first-order gradient method with SARAH variance reduction and gradient tracking.
result Achieves εε-accurate first-order stationary point with improved gradient complexity.

The main theme of this work is a unifying algorithm, \textbf{L}oop\textbf{L}ess \textbf{S}ARAH (L2S) for problems formulated as summation of nn individual loss functions. L2S broadens a recently developed variance reduction method known as SARAH. To find an εε-accurate solution, L2S enjoys a complexity of ${\cal O}\b…

2019-06-05abs ↗pdf ↗

The total complexity (measured as the total number of gradient computations) of a stochastic first-order optimization algorithm that finds a first-order stationary point of a finite-sum smooth nonconvex objective function F(w)=1ni=1nfi(w)F(w)=\frac{1}{n} \sum_{i=1}^n f_i(w) has been proven to be at least Ω(n/ε)Ω(\sqrt{n}/ε) for $n \leq …

2019-01-22abs ↗pdf ↗

The variance reduction class of algorithms including the representative ones, SVRG and SARAH, have well documented merits for empirical risk minimization problems. However, they require grid search to tune parameters (step size and the number of iterations per inner loop) for optimal performance. This work introduces `…

2019-08-25abs ↗pdf ↗

A new hybrid algorithm reduces stochastic gradient evaluations for nonconvex optimization.

problem Solving stochastic composite nonconvex optimization problems efficiently.
method Proposes a new hybrid variance-reduced proximal gradient method with a stochastic gradient estimator.
result Achieves optimal stochastic oracle complexity bound with one less gradient evaluation.

Adaptivity is an important yet under-studied property in modern optimization theory. The gap between the state-of-the-art theory and the current practice is striking in that algorithms with desirable theoretical guarantees typically involve drastically different settings of hyperparameters, such as step-size schemes an…

2020-02-13abs ↗pdf ↗

In this paper, we study and analyze the mini-batch version of StochAstic Recursive grAdient algoritHm (SARAH), a method employing the stochastic recursive gradient, for solving empirical loss minimization for the case of nonconvex losses. We provide a sublinear convergence rate (to stationary points) for general noncon…

2017-05-20abs ↗pdf ↗

The main goal of this work is equipping convex and nonconvex problems with Barzilai-Borwein (BB) step size. With the adaptivity of BB step sizes granted, they can fail when the objective function is not strongly convex. To overcome this challenge, the key idea here is to bridge (non)convex problems and strongly convex …

2019-10-15abs ↗pdf ↗

Two new Frank-Wolfe algorithms improve convergence for constrained optimization.

problem Solving optimization problems with structured constraints in machine learning.
method Two new variants of the Frank-Wolfe (FW) method for stochastic finite-sum minimization.
result Best convergence guarantees for convex and non-convex objective functions.

LaPSRL achieves optimal regret for isoperimetric RL distributions.

problem Designing RL algorithms with sublinear regret for non-log-concave distributions.
method Posterior Sampling (PSRL) and Langevin sampling (LaPSRL) for isoperimetric distributions.
result LaPSRL achieves order-optimal regret and subquadratic complexity.

Paper proposes faster method to find local minima in nonconvex optimization.

problem Escaping saddle points and finding local minima in nonconvex optimization.
method LENA (Last stEp shriNkAge) framework for faster perturbed stochastic gradient methods.
result LENA finds (ε,εH)(ε, ε_{H})-approximate local minima within ildeO(ε3+εH6) ilde O(ε^{-3} + ε_{H}^{-6}) evaluations.

New lower bounds for gradient methods in strongly convex finite-sum optimization.

problem Developing tight lower bounds for randomized gradient methods in finite-sum optimization.
method Deriving tight lower complexity bounds for SAG, SAGA, SVRG, SARAH, and related methods.
result Tight matches between lower bounds and upper bounds for various methods under specific conditions.

Develops an accelerated algorithm for solving nonmonotone generalized equations.

problem Solving nonmonotone generalized equations with possibly non-accelerated schemes.
method Combines Nesterov's acceleration and variance-reduction techniques for a class of generalized equations.
result Achieves O(1/k2)\mathcal{O}(1/k^2) convergence rates, improving upon non-accelerated counterparts.

Develops variance-reduced methods for solving generalized equations.

problem Solving a class of generalized equations, including minimization, minimax, and variational inequalities.
method Integrates accelerated operator splitting, fixed-point methods, and variance reduction techniques.
result Achieves both O(1/k2)\mathcal{O}(1/k^2) and o(1/k2)o(1/k^2) convergence rates on the expected squared norm of the FBS residual.

New HMC framework reduces variance for sampling from log-concave distributions.

problem Efficient sampling from log-concave distributions with high precision.
method Unified formulation of biased and unbiased variance reduction methods for HMC.
result Unbiased and biased gradient estimators achieve different gradient complexities and accuracy.

Improved optimization technique reduces training complexity for non-convex problems.

problem Training non-convex optimization problems with exploding gradients.
method Employed variance reduction technique (SPIDER) with carefully designed learning rate.
result Improved stochastic gradient complexity to O(ε3)O(ε^{-3}) for εε-stationary solutions.

New variance-reduction methods solve stochastic composite inclusions.

problem Solving nonmonotone stochastic composite inclusions.
method Developed unbiased and biased variance-reduced estimators for FRBS method.
result Achieved best oracle complexities for finite-sum and expectation settings.

Examines algorithmic modeling across three cultures.

problem Tackles algorithmic modeling in different cultural contexts.
method Uses parametric regressions, interpretable algorithms, and complex algorithms.
result Extension of Leo Breiman's thesis to include cultural differences.

Playing repeated matrix games (RMG) while maximizing the cumulative returns is a basic method to evaluate multi-agent learning (MAL) algorithms. Previous work has shown that UCBUCB, M3M3, SS or Exp3Exp3 algorithms have good behaviours on average in RMG. Besides, hedging algorithms have been shown to be effective on predi…

2018-10-15abs ↗pdf ↗

Meta-algorithm selection aims to choose the best algorithm selector for a given problem instance.

problem Selecting the best algorithm selector for a specific problem instance.
method Apply algorithm selection to the selection of other algorithms (meta-algorithm selection).
result Meta-algorithm selection can be beneficial in some cases but faces challenges in solving the meta-level problem.

Combines multiple bandit algorithms to create a nearly optimal single algorithm.

problem Designing a single bandit algorithm that performs nearly as well as the best individual algorithm in a stochastic environment.
method Develops two general corralling algorithms that achieve favorable regret guarantees.
result The regret of the corralling algorithms is no worse than the best individual algorithm's performance.

The exchange algorithm is studied for its convergence and asymptotic variance.

problem Theoretical limitations of the exchange algorithm in sampling from doubly-intractable distributions.
method Theoretical analysis of the exchange algorithm's convergence speed and asymptotic variance.
result The exchange algorithm converges at a geometric rate and satisfies a Central Limit Theorem.

Algorithm design is a laborious process and often requires many iterations of ideation and validation. In this paper, we explore automating algorithm design and present a method to learn an optimization algorithm, which we believe to be the first method that can automatically discover a better algorithm. We approach th…

2016-06-06abs ↗pdf ↗

Paper proposes a reinforcement learning framework for efficient hyper-parameter tuning of stochastic optimization algorithms.

problem Efficient tuning of hyper-parameters for stochastic optimization algorithms.
method Modeling hyper-parameter tuning as a Markov decision process and using policy gradient algorithms.
result The proposed framework significantly reduces the time required for hyper-parameter tuning compared to Bayesian optimization.