The FF Planning System: Fast Plan Generation Through Heuristic Search

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 informa tion can be extracted and used to prune the search space FF was the most successful automatic planner at the recent AIPS planning competition We review the results of the competition give data for other benchmark domains and investigate the reasons for the runtime performance of FF compared to HSP