AAAI Publications, Fourth Annual Symposium on Combinatorial Search

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A Polynomial-Time Algorithm for Non-Optimal Multi-Agent Pathfinding
Mokhtar M. Khorshid, Robert C. Holte, Nathan R. Sturtevant

Last modified: 2011-07-05


Multi-agent pathfinding, where multiple agents must travel to their goal locations without getting stuck, has been studied in both theoretical and practical contexts, with a variety of both optimal and sub-optimal algorithms proposed for solving problems. Recent work has shown that there is a linear-time check for whether a multi-agent pathfinding problem can be solved in a tree, however this was not used to actually produce solutions. In this paper we provide a constructive proof of how to solve multi-agent pathfinding problems in a tree that culminates in a novel approach that we call the tree-based agent swapping strategy (TASS). Experimental results showed that TASS can find solutions to the multi-agent pathfinding problem on a highly crowded tree with 1000 nodes and 996 agents in less than 8 seconds. These results are far more efficient and general than existing work, suggesting that TASS is a productive line of study for multi-agent pathfinding.


multi-agent; pathfinding; cooperative; tree; search

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