Speeding Up the NSGA-II With a Simple Tie-Breaking Rule

Fuente: arXiv
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Main Authors: Doerr, Benjamin, Ivan, Tudor, Krejca, Martin S.
Format: Preprint
Published: 2024
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author Doerr, Benjamin
Ivan, Tudor
Krejca, Martin S.
author_facet Doerr, Benjamin
Ivan, Tudor
Krejca, Martin S.
contents The non-dominated sorting genetic algorithm~II (NSGA-II) is the most popular multi-objective optimization heuristic. Recent mathematical runtime analyses have detected two shortcomings in discrete search spaces, namely, that the NSGA-II has difficulties with more than two objectives and that it is very sensitive to the choice of the population size. To overcome these difficulties, we analyze a simple tie-breaking rule in the selection of the next population. Similar rules have been proposed before, but have found only little acceptance. We prove the effectiveness of our tie-breaking rule via mathematical runtime analyses on the classic OneMinMax, LeadingOnesTrailingZeros, and OneJumpZeroJump benchmarks. We prove that this modified NSGA-II can optimize the three benchmarks efficiently also for many objectives, in contrast to the exponential lower runtime bound previously shown for OneMinMax with three or more objectives. For the bi-objective problems, we show runtime guarantees that do not increase when moderately increasing the population size over the minimum admissible size. For example, for the OneJumpZeroJump problem with representation length $n$ and gap parameter $k$, we show a runtime guarantee of $O(\max\{n^{k+1},Nn\})$ function evaluations when the population size is at least four times the size of the Pareto front. For population sizes larger than the minimal choice $N = Θ(n)$, this result improves considerably over the $Θ(Nn^k)$ runtime of the classic NSGA-II.
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id arxiv_https___arxiv_org_abs_2412_11931
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Speeding Up the NSGA-II With a Simple Tie-Breaking Rule
Doerr, Benjamin
Ivan, Tudor
Krejca, Martin S.
Neural and Evolutionary Computing
The non-dominated sorting genetic algorithm~II (NSGA-II) is the most popular multi-objective optimization heuristic. Recent mathematical runtime analyses have detected two shortcomings in discrete search spaces, namely, that the NSGA-II has difficulties with more than two objectives and that it is very sensitive to the choice of the population size. To overcome these difficulties, we analyze a simple tie-breaking rule in the selection of the next population. Similar rules have been proposed before, but have found only little acceptance. We prove the effectiveness of our tie-breaking rule via mathematical runtime analyses on the classic OneMinMax, LeadingOnesTrailingZeros, and OneJumpZeroJump benchmarks. We prove that this modified NSGA-II can optimize the three benchmarks efficiently also for many objectives, in contrast to the exponential lower runtime bound previously shown for OneMinMax with three or more objectives. For the bi-objective problems, we show runtime guarantees that do not increase when moderately increasing the population size over the minimum admissible size. For example, for the OneJumpZeroJump problem with representation length $n$ and gap parameter $k$, we show a runtime guarantee of $O(\max\{n^{k+1},Nn\})$ function evaluations when the population size is at least four times the size of the Pareto front. For population sizes larger than the minimal choice $N = Θ(n)$, this result improves considerably over the $Θ(Nn^k)$ runtime of the classic NSGA-II.
title Speeding Up the NSGA-II With a Simple Tie-Breaking Rule
topic Neural and Evolutionary Computing
url https://arxiv.org/abs/2412.11931