Landmarks for Numeric Planning Problems

The paper generalises the notion of landmarks for reasoning about planning problems involving propositional and numeric variables. Intuitively, numeric landmarks are regions in the metric space defined by the problem whose crossing is necessary for its resolution. The paper proposes a relaxation-based method for their automated extraction directly from the problem structure, and shows how to exploit them to infer what we call disjunctive and additive hybrid action landmarks. The justification of such a disjunctive representation results from the intertwined propositional and numeric structure of the problem. The paper exercises their use in two novel admissible LP-Based numeric heuristics, and reports experiments on cost-optimal numeric planning problems. Results show the heuristics are more informed and effective than previous work for problems involving a higher number of (sub)goals.

Authors

• Enrico Scala University of Brescia
• Patrik Haslum Australian National University
• Daniele Magazzeni J.P. Morgan AI Research
• Sylvie Thiébaux School of Computing, The Australian National University LAAS-CNRS, Université de Toulouse

Keywords

• Planning and Scheduling: Planning and Scheduling
• Planning and Scheduling: Search in Planning and Scheduling
• Planning and Scheduling: Temporal and Hybrid Planning