Enriching Non-Parametric Bidirectional Search Algorithms — Extended Abstract
Shahaf Shperberg, Ariel Felner, Nathan Sturtevant, Solomon Eyal Shimony, Avi Hayoun · Proceedings of the International Symposium on Combinatorial Search · 2021
NBS is a non-parametric bidirectional search algorithm, proved to expand at most twice the number of node expansions required to verify the optimality of a solution. We introduce new variants of NBS that are aimed at finding all optimal solutions. We then introduce an algorithmic framework that includes NBS as a special case. Finally, we introduce DVCBS, a new algorithm in this framework that aims to further reduce the number of expansions. Unlike NBS, DVCBS does not have any worst-case bound guarantees, but in practice it outperforms NBS in verifying the optimality of solutions.