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Main Authors: Ardizzoni, S., Saccani, I., Consolini, L., Locatelli, M.
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2304.01765
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author Ardizzoni, S.
Saccani, I.
Consolini, L.
Locatelli, M.
author_facet Ardizzoni, S.
Saccani, I.
Consolini, L.
Locatelli, M.
contents Among sub-optimal MAPF solvers, rule-based algorithms are particularly appealing since they are complete. Even in crowded scenarios, they allow finding a feasible solution that brings each agent to its target, preventing deadlock situations. However, generally, rule-based algorithms provide solutions that are much longer than the optimal one. The main contribution of this paper is the introduction of an iterative local search procedure in MAPF. We start from a feasible suboptimal solution and we perform a local search in a neighborhood of this solution, to find a shorter one. Iteratively, we repeat this procedure until the solution cannot be shortened any longer. At the end, we obtain a solution, that is still sub-optimal, but, in general, of much better quality than the initial one. We use dynamic programming for the local search procedure. Under this respect, the fact that our search is local is fundamental to reduce the time complexity of the algorithm. Indeed, if we apply a standard dynamic programming the number of explored states grows exponentially with the number of agents. As we will see, the introduction of a locality constraint allows solving the (local) dynamic programming problem in a time that grows only polynomially with respect to the number of agents.
format Preprint
id arxiv_https___arxiv_org_abs_2304_01765
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Local Optimization of MAPF solutions on Directed Graphs
Ardizzoni, S.
Saccani, I.
Consolini, L.
Locatelli, M.
Optimization and Control
Among sub-optimal MAPF solvers, rule-based algorithms are particularly appealing since they are complete. Even in crowded scenarios, they allow finding a feasible solution that brings each agent to its target, preventing deadlock situations. However, generally, rule-based algorithms provide solutions that are much longer than the optimal one. The main contribution of this paper is the introduction of an iterative local search procedure in MAPF. We start from a feasible suboptimal solution and we perform a local search in a neighborhood of this solution, to find a shorter one. Iteratively, we repeat this procedure until the solution cannot be shortened any longer. At the end, we obtain a solution, that is still sub-optimal, but, in general, of much better quality than the initial one. We use dynamic programming for the local search procedure. Under this respect, the fact that our search is local is fundamental to reduce the time complexity of the algorithm. Indeed, if we apply a standard dynamic programming the number of explored states grows exponentially with the number of agents. As we will see, the introduction of a locality constraint allows solving the (local) dynamic programming problem in a time that grows only polynomially with respect to the number of agents.
title Local Optimization of MAPF solutions on Directed Graphs
topic Optimization and Control
url https://arxiv.org/abs/2304.01765