Similarity-based Portfolio Construction for Black-box Optimization

Fuente: arXiv
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Main Authors: Dinu, Catalin-Viorel, Vermetten, Diederick, Doerr, Carola
Format: Preprint
Published: 2026
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author Dinu, Catalin-Viorel
Vermetten, Diederick
Doerr, Carola
author_facet Dinu, Catalin-Viorel
Vermetten, Diederick
Doerr, Carola
contents In black-box optimization, a central question is which algorithm to use to solve a given, previously unseen, problem. Selecting a single algorithm, however, entails inherent risks: inaccuracies in the selector may lead to poor choices, and even well-performing algorithms with high variance can yield unsatisfactory results in a single run. A natural remedy is to split the evaluation budget across multiple runs of potentially different algorithms. Such sequential algorithm portfolios benefit from variance reduction and complementarities between algorithms, often outperforming approaches that allocate the entire budget to a single solver. While effective portfolios can be constructed post-hoc, transferring this idea to the algorithm selection setting is non-trivial. We show that a naive portfolio constructed over the full training set already outperforms the strongest traditional baseline, the virtual best solver. We then propose a simple yet effective k-nearest-neighbor-based finetuning approach to construct portfolios tailored to unseen instances, yielding further improvements and highlighting the effectiveness of portfolio selection in fixed-budget black-box optimization.
format Preprint
id arxiv_https___arxiv_org_abs_2604_18196
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Similarity-based Portfolio Construction for Black-box Optimization
Dinu, Catalin-Viorel
Vermetten, Diederick
Doerr, Carola
Neural and Evolutionary Computing
In black-box optimization, a central question is which algorithm to use to solve a given, previously unseen, problem. Selecting a single algorithm, however, entails inherent risks: inaccuracies in the selector may lead to poor choices, and even well-performing algorithms with high variance can yield unsatisfactory results in a single run. A natural remedy is to split the evaluation budget across multiple runs of potentially different algorithms. Such sequential algorithm portfolios benefit from variance reduction and complementarities between algorithms, often outperforming approaches that allocate the entire budget to a single solver. While effective portfolios can be constructed post-hoc, transferring this idea to the algorithm selection setting is non-trivial. We show that a naive portfolio constructed over the full training set already outperforms the strongest traditional baseline, the virtual best solver. We then propose a simple yet effective k-nearest-neighbor-based finetuning approach to construct portfolios tailored to unseen instances, yielding further improvements and highlighting the effectiveness of portfolio selection in fixed-budget black-box optimization.
title Similarity-based Portfolio Construction for Black-box Optimization
topic Neural and Evolutionary Computing
url https://arxiv.org/abs/2604.18196