Incremental Clustering and Expansion for Faster Optimal Planning in Dec-POMDPs
Author(s)Oliehoek, Frans A.; Spaan, Matthijs T. J.; Amato, Christopher; Whiteson, Shimon
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Incremental Clustering and Expansion for Faster Optimal Planning in Decentralized POMDPs
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This article presents the state-of-the-art in optimal solution methods for decentralized partially observable Markov decision processes (Dec-POMDPs), which are general models for collaborative multiagent planning under uncertainty. Building off the generalized multiagent A* (GMAA*) algorithm, which reduces the problem to a tree of one-shot collaborative Bayesian games (CBGs), we describe several advances that greatly expand the range of Dec-POMDPs that can be solved optimally. First, we introduce lossless incremental clustering of the CBGs solved by GMAA*, which achieves exponential speedups without sacrificing optimality. Second, we introduce incremental expansion of nodes in the GMAA* search tree, which avoids the need to expand all children, the number of which is in the worst case doubly exponential in the node's depth. This is particularly beneficial when little clustering is possible. In addition, we introduce new hybrid heuristic representations that are more compact and thereby enable the solution of larger Dec-POMDPs. We provide theoretical guarantees that, when a suitable heuristic is used, both incremental clustering and incremental expansion yield algorithms that are both complete and search equivalent. Finally, we present extensive empirical results demonstrating that GMAA*-ICE, an algorithm that synthesizes these advances, can optimally solve Dec-POMDPs of unprecedented size.
DepartmentMassachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
Journal of Artificial Intelligence Research
Association for the Advancement of Artificial Intelligence
Oliehoek, Frans A.; Spaan, Matthijs T. J.; Amato, Christopher; Whiteson, Shimon. "Incremental Clustering and Expansion for Faster Optimal Planning in Decentralized POMDPs." Journal of Artificial Intelligence Research 46 (2013): 449-509. © Copyright 2013 AI Access Foundation, Inc.
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