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A random-key optimizer for combinatorial optimization

A random-key optimizer for combinatorial optimization
A random-key optimizer for combinatorial optimization
This paper presents the Random-Key Optimizer (RKO), a versatile and efficient stochastic local search method tailored for combinatorial optimization problems. Using the random-key concept, RKO encodes solutions as vectors of random keys that are subsequently decoded into feasible solutions via problem-specific decoders. The RKO framework is able to combine a plethora of classic metaheuristics, each capable of operating independently or in parallel, with solution sharing facilitated through an elite solution pool. This modular approach allows for the adaptation of various metaheuristics, including simulated annealing, iterated local search, and greedy randomized adaptive search procedures, among others. The efficacy of the RKO framework, implemented in C++, is demonstrated through its application to three NP-hard combinatorial optimization problems: the alpha-neighborhood p-median problem, the tree of hubs location problem, and the node-capacitated graph partitioning problem. The results highlight the framework's ability to produce high-quality solutions across diverse problem domains, underscoring its potential as a robust tool for combinatorial optimization.
cs.AI, 90-02, 90B40, 90C27, G.1.6; G.2.1; I.2.8
1381-1231
Chaves, Antônio Augusto
f48121e1-7f5f-41b5-91d0-36503578e4dd
Resende, Mauricio G. C.
2fe5611a-bc33-4b3a-a772-10f96d8e2ab9
Schuetz, Marin J.A.
7427a2be-ece6-4d80-b58f-86e700484e8b
Brubaker, J.K.
fc7e4e4e-15f0-45f2-b6af-0aacffdde130
Katzgraber, H.G.
e4dd4713-cc39-4461-ba04-bdb7dcaa9195
Arruda, Edilson F.
8eb3bd83-e883-4bf3-bfbc-7887c5daa911
Silva, Ricardo M.A.
7b7d9490-f633-48a1-84a5-a36d51543785
Chaves, Antônio Augusto
f48121e1-7f5f-41b5-91d0-36503578e4dd
Resende, Mauricio G. C.
2fe5611a-bc33-4b3a-a772-10f96d8e2ab9
Schuetz, Marin J.A.
7427a2be-ece6-4d80-b58f-86e700484e8b
Brubaker, J.K.
fc7e4e4e-15f0-45f2-b6af-0aacffdde130
Katzgraber, H.G.
e4dd4713-cc39-4461-ba04-bdb7dcaa9195
Arruda, Edilson F.
8eb3bd83-e883-4bf3-bfbc-7887c5daa911
Silva, Ricardo M.A.
7b7d9490-f633-48a1-84a5-a36d51543785

Chaves, Antônio Augusto, Resende, Mauricio G. C., Schuetz, Marin J.A., Brubaker, J.K., Katzgraber, H.G., Arruda, Edilson F. and Silva, Ricardo M.A. (2025) A random-key optimizer for combinatorial optimization. Journal of Heuristics, 31, [32]. (doi:10.48550/arXiv.2411.04293).

Record type: Article

Abstract

This paper presents the Random-Key Optimizer (RKO), a versatile and efficient stochastic local search method tailored for combinatorial optimization problems. Using the random-key concept, RKO encodes solutions as vectors of random keys that are subsequently decoded into feasible solutions via problem-specific decoders. The RKO framework is able to combine a plethora of classic metaheuristics, each capable of operating independently or in parallel, with solution sharing facilitated through an elite solution pool. This modular approach allows for the adaptation of various metaheuristics, including simulated annealing, iterated local search, and greedy randomized adaptive search procedures, among others. The efficacy of the RKO framework, implemented in C++, is demonstrated through its application to three NP-hard combinatorial optimization problems: the alpha-neighborhood p-median problem, the tree of hubs location problem, and the node-capacitated graph partitioning problem. The results highlight the framework's ability to produce high-quality solutions across diverse problem domains, underscoring its potential as a robust tool for combinatorial optimization.

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More information

Published date: 26 September 2025
Additional Information: 16 figures, 8 tables
Keywords: cs.AI, 90-02, 90B40, 90C27, G.1.6; G.2.1; I.2.8

Identifiers

Local EPrints ID: 495864
URI: http://eprints.soton.ac.uk/id/eprint/495864
ISSN: 1381-1231
PURE UUID: 05ee29d8-3a84-4191-b6fa-c6295f38e7e9
ORCID for Edilson F. Arruda: ORCID iD orcid.org/0000-0002-9835-352X

Catalogue record

Date deposited: 26 Nov 2024 17:41
Last modified: 03 Oct 2025 02:03

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Contributors

Author: Antônio Augusto Chaves
Author: Mauricio G. C. Resende
Author: Marin J.A. Schuetz
Author: J.K. Brubaker
Author: H.G. Katzgraber
Author: Edilson F. Arruda ORCID iD
Author: Ricardo M.A. Silva

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