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Gradient Is All You Need? (arxiv.org)
1 point by fofoz on Jun 23, 2023 | hide | past | pdf | discuss on HN

In plain words: A swarm of points that only test function values and share information behaves like gradient descent with random nudges, letting it hop over bumps instead of following the slope. Unlike ordinary gradient descent, it is proven to reach the lowest point for rough functions.

Abstract · Gradient is All You Need? How Consensus-Based Optimization can be Interpreted as a Stochastic Relaxation of Gradient Descent

In this paper, we provide a novel analytical perspective on the theoretical understanding of gradient-based learning algorithms by interpreting consensus-based optimization (CBO), a recently proposed multi-particle derivative-free optimization method, as a stochastic relaxation of gradient descent. Remarkably, we observe that through communication of the particles, CBO exhibits a stochastic gradient descent (SGD)-like behavior despite solely relying on evaluations of the objective function. The fundamental value of such link between CBO and SGD lies in the fact that CBO is provably globally convergent to global minimizers for ample classes of nonsmooth and nonconvex objective functions. Hence, on the one side, we offer a novel explanation for the success of stochastic relaxations of gradient descent by furnishing useful and precise insights that explain how problem-tailored stochastic perturbations of gradient descent (like the ones induced by CBO) overcome energy barriers and reach deep levels of nonconvex functions. On the other side, and contrary to the conventional wisdom for which derivative-free methods ought to be inefficient or not to possess generalization abilities, our results unveil an intrinsic gradient descent nature of heuristics. Instructive numerical illustrations support the provided theoretical insights.

Konstantin Riedl, Timo Klock, Carina Geldhauser, Massimo Fornasier
arXiv:2306.09778 · cs.LG, math.NA, math.OC, stat.ML · submitted Jun 16, 2023 · updated Feb 27, 2026
abstract · pdf · html · 49 pages, 5 figures

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