Derivative-Free Optimization via Finite Difference Approximation: An Experimental Study

Fuente: arXiv
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Main Authors: Du-Yi, Wang, Guo, Liang, Guangwu, Liu, Kun, Zhang
Format: Preprint
Published: 2024
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author Du-Yi, Wang
Guo, Liang
Guangwu, Liu
Kun, Zhang
author_facet Du-Yi, Wang
Guo, Liang
Guangwu, Liu
Kun, Zhang
contents Derivative-free optimization (DFO) is vital in solving complex optimization problems where only noisy function evaluations are available through an oracle. Within this domain, DFO via finite difference (FD) approximation has emerged as a powerful method. Two classical approaches are the Kiefer-Wolfowitz (KW) and simultaneous perturbation stochastic approximation (SPSA) algorithms, which estimate gradients using just two samples in each iteration to conserve samples. However, this approach yields imprecise gradient estimators, necessitating diminishing step sizes to ensure convergence, often resulting in slow optimization progress. In contrast, FD estimators constructed from batch samples approximate gradients more accurately. While gradient descent algorithms using batch-based FD estimators achieve more precise results in each iteration, they require more samples and permit fewer iterations. This raises a fundamental question: which approach is more effective -- KW-style methods or DFO with batch-based FD estimators? This paper conducts a comprehensive experimental comparison among these approaches, examining the fundamental trade-off between gradient estimation accuracy and iteration steps. Through extensive experiments in both low-dimensional and high-dimensional settings, we demonstrate a surprising finding: when an efficient batch-based FD estimator is applied, its corresponding gradient descent algorithm generally shows better performance compared to classical KW and SPSA algorithms in our tested scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2411_00112
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Derivative-Free Optimization via Finite Difference Approximation: An Experimental Study
Du-Yi, Wang
Guo, Liang
Guangwu, Liu
Kun, Zhang
Machine Learning
Optimization and Control
90-05
I.6.1; I.6.6
Derivative-free optimization (DFO) is vital in solving complex optimization problems where only noisy function evaluations are available through an oracle. Within this domain, DFO via finite difference (FD) approximation has emerged as a powerful method. Two classical approaches are the Kiefer-Wolfowitz (KW) and simultaneous perturbation stochastic approximation (SPSA) algorithms, which estimate gradients using just two samples in each iteration to conserve samples. However, this approach yields imprecise gradient estimators, necessitating diminishing step sizes to ensure convergence, often resulting in slow optimization progress. In contrast, FD estimators constructed from batch samples approximate gradients more accurately. While gradient descent algorithms using batch-based FD estimators achieve more precise results in each iteration, they require more samples and permit fewer iterations. This raises a fundamental question: which approach is more effective -- KW-style methods or DFO with batch-based FD estimators? This paper conducts a comprehensive experimental comparison among these approaches, examining the fundamental trade-off between gradient estimation accuracy and iteration steps. Through extensive experiments in both low-dimensional and high-dimensional settings, we demonstrate a surprising finding: when an efficient batch-based FD estimator is applied, its corresponding gradient descent algorithm generally shows better performance compared to classical KW and SPSA algorithms in our tested scenarios.
title Derivative-Free Optimization via Finite Difference Approximation: An Experimental Study
topic Machine Learning
Optimization and Control
90-05
I.6.1; I.6.6
url https://arxiv.org/abs/2411.00112