Improving LaCAM for Scalable Eventually Optimal Multi-Agent Pathfinding
This work addresses scalability in multi-agent pathfinding for robotics and AI applications, representing an incremental improvement over existing methods.
The study tackled the problem of scaling multi-agent pathfinding by extending the LaCAM algorithm to ensure eventual optimality and faster initial solutions, resulting in LaCAM* solving 99% of benchmark instances with up to a thousand agents within ten seconds while guaranteeing convergence to optima.
This study extends the recently-developed LaCAM algorithm for multi-agent pathfinding (MAPF). LaCAM is a sub-optimal search-based algorithm that uses lazy successor generation to dramatically reduce the planning effort. We present two enhancements. First, we propose its anytime version, called LaCAM*, which eventually converges to optima, provided that solution costs are accumulated transition costs. Second, we improve the successor generation to quickly obtain initial solutions. Exhaustive experiments demonstrate their utility. For instance, LaCAM* sub-optimally solved 99% of the instances retrieved from the MAPF benchmark, where the number of agents varied up to a thousand, within ten seconds on a standard desktop PC, while ensuring eventual convergence to optima; developing a new horizon of MAPF algorithms.