The FF Planning System: Fast Plan Generation Through Heuristic Search

Understand

We describe and evaluate the algorithmic techniques that are used in the FF planning system.

• Like the HSP system, FF relies on forward state space search, using a heuristic that estimates goal distances by ignoring delete lists.
• Unlike HSP's heuristic, our method does not assume facts to be independent.
• We introduce a novel search strategy that combines hill-climbing with systematic search, and we show how other powerful heuristic information can be extracted and used to prune the search space.