,
Pierre Flener
,
Justin Pearson
Creative Commons Attribution 4.0 International license
In large neighbourhood search (LNS), an incumbent initial solution is incrementally improved by selecting a subset of the variables, called the freeze set, and fixing them to their values in the incumbent solution, while a value for each remaining variable is found and assigned via solving (such as constraint programming-style propagation and search). Much research has been performed on finding generic and problem-specific LNS selection heuristics that select freeze sets that lead to high-quality solutions. In constraint-based local search (CBLS), the relations between the variables via the constraints are fundamental and well-studied, as they capture dependencies of the variables. In this paper, we apply these ideas from CBLS to the LNS context, presenting the novel dependency curation scheme, which exploits them to find a low-cardinality set of variables that the freeze set of any selection heuristic should be a subset of. The scheme often improves the overall performance of generic selection heuristics. Even when the scheme is used with a naïve generic selection heuristic that selects random freeze sets, the performance is competitive with more elaborate generic selection heuristics.
@InProceedings{knutarlewander_et_al:LIPIcs.CP.2025.20,
author = {Knutar Lewander, Frej and Flener, Pierre and Pearson, Justin},
title = {{Dependency-Curated Large Neighbourhood Search}},
booktitle = {31st International Conference on Principles and Practice of Constraint Programming (CP 2025)},
pages = {20:1--20:17},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-380-5},
ISSN = {1868-8969},
year = {2025},
volume = {340},
editor = {de la Banda, Maria Garcia},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CP.2025.20},
URN = {urn:nbn:de:0030-drops-238810},
doi = {10.4230/LIPIcs.CP.2025.20},
annote = {Keywords: Combinatorial Optimisation, Large Neighbourhood Search (LNS), Constraint-Based Local Search (CBLS)}
}
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