- Keywords: Symbolic Search, Planning Pattern Database, Portfolio Planning
- Abstract: The optimal track is one the most exiting events in the International Planning Competition (IPC). In this position paper we argue that —despite of not winning the competition— symbolic search and pattern databases were likely the most influential planning approaches in the latest IPC in 2018, and, in continuation to the precursor IPC in 2014, should be considered as candidates for the current state-of-the-art. Five of the Top 6 planners in the 2018 competition, namely Complementary (1 and 2), Planning-PDBs, Symbolic-Bidirectional, and Scorpion are based on these technologies. These planners use the same technology across all domains and plan in one state space. The winner of IPC 2018 with an ~ 1% lead in problems being solved, however, is a so-called portfolio planner, consisting of a selection of many different planners, one of which is chosen in a classifier that was trained on a manually selected set of benchmark instances. In about half of its successful runs, it called the winner of the previous IPC, which in turn is based on symbolic search. We argue on whether or not to exclude portfolios from the IPC is possible and wanted.
- Track: short (15 minutes)