AAAI Publications, Tenth Annual Symposium on Combinatorial Search

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Symbolic Leaf Representation in Decoupled Search
Daniel Gnad, Álvaro Torralba, Jörg Hoffmann

Last modified: 2017-06-06


Star-Topology Decoupled Search has recently been introduced in classical planning. It splits the planning task into a set of components whose dependencies take a star structure, where one center component interacts with possibly many leaf components. Here we address a weakness of decoupled search, namely large leaf components, whose state space is enumerated explicitly. We propose a symbolic representation of the leaf state spaces via decision diagrams, which can be dramatically smaller, and also more runtime efficient. We further introduce a symbolic version of the LM-cut heuristic, that nicely connects to our new leaf representation. We show empirically that the symbolic representation indeed pays off when the leaf components are large.

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