Research reports

Strong error analysis for stochastic gradient descent optimization algorithms

by A. Jentzen and B. Kuckuck and A. Neufeld and P. von Wurstemberger

(Report number 2018-03)

Abstract
Stochastic gradient descent (SGD) optimization algorithms are key ingredients in a series of machine learning applications. In this article we perform a rigorous strong error analysis for SGD optimization algorithms. In particular, we prove for every arbitrarily small \(\varepsilon \in (0,\infty)\) and every arbitrarily large \(p\in (0,\infty)\) that the considered SGD optimization algorithm converges in the strong \(L^p\)-sense with order \(\frac{1}{2}-\varepsilon\) to the global minimum of the objective function of the considered stochastic approximation problem under standard convexity-type assumptions on the objective function and relaxed assumptions on the moments of the stochastic errors appearing in the employed SGD optimization algorithm. The key ideas in our convergence proof are, first, to employ techniques from the theory of Lyapunov-type functions for dynamical systems to develop a general convergence machinery for SGD optimization algorithms based on such functions, then, to apply this general machinery to concrete Lyapunov-type functions with polynomial structures, and, thereafter, to perform an induction argument along the powers appearing in the Lyapunov-type functions in order to achieve for every arbitrarily large \( p \in (0,\infty) \) strong \(L^p\)-convergence rates. This article also contains an extensive review of results on SGD optimization algorithms in the scientific literature.

Keywords:

BibTeX
@Techreport{JKNv18_757,
  author = {A. Jentzen and B. Kuckuck and A. Neufeld and P. von Wurstemberger},
  title = {Strong error analysis for stochastic gradient descent optimization algorithms},
  institution = {Seminar for Applied Mathematics, ETH Z{\"u}rich},
  number = {2018-03},
  address = {Switzerland},
  url = {https://www.sam.math.ethz.ch/sam_reports/reports_final/reports2018/2018-03.pdf },
  year = {2018}
}

Disclaimer
© Copyright for documents on this server remains with the authors. Copies of these documents made by electronic or mechanical means including information storage and retrieval systems, may only be employed for personal use. The administrators respectfully request that authors inform them when any paper is published to avoid copyright infringement. Note that unauthorised copying of copyright material is illegal and may lead to prosecution. Neither the administrators nor the Seminar for Applied Mathematics (SAM) accept any liability in this respect. The most recent version of a SAM report may differ in formatting and style from published journal version. Do reference the published version if possible (see SAM Publications).

JavaScript has been disabled in your browser