We introduce a new algorithm for multi-agent path finding, derived from the idea of meta-agent conflict-based search (MA-CBS). MA-CBS is a recently proposed algorithm for the multi-agent path finding problem. The algorithm is an extension of Conflict-Based Search (CBS), which automatically merges conflicting agents into meta-agents if the number of conflicts exceeds a certain threshold. However, the decision to merge agents is made according to an empirically chosen fixed threshold on the number of conflicts. The best threshold depends both on the domain and on the number of agents, and the nature of the dependence is not clearly understood.
We suggest a justification for the use of a fixed threshold on the number of conflicts based on the analysis of a model problem. Following the suggested justification, we introduce a new algorithm, which differs in the ways when and how meta-agents are created and handled during search. The new algorithm exhibits considerably better performance compared to the original algorithm. The new algorithm is evaluated on several sets of problems, chosen to highlight different aspects of the algorithm.
This is a short version of Justifying and Improving MA-CBS.