A Case Study on the Importance of Low-Level Algorithmic Details in Domain-Independent Heuristics

It is known that seemingly small details such as tie-breaking among nodes with the same f-cost can significantly affect the performance of a best-first search algorithm on many domains (Asai and Fukunaga 2017). In this paper, we show that low-level algorithmic details of domain-independent planning heuristics can have a surprisingly large impact on search performance. As a case study, we consider the well-known FF heuristic (hff ) (Hoffmann and Nebel 2001).