Speculative search: An efficient search algorithm for limited memory

The authors present a novel algorithm, speculative branch and bound, for performing heuristic search in restricted memory. Speculative branch-and-bound combines elements of best-first and depth-first searches. The authors describe the search and a variant, SIDA* that is analogous to A*. They show how they are related to such searches as IDA* and MA* show how to add pruning to SIDA* and give performance results. SIDA* is superior to IDA* and competitive with MA* in the number of nodes it expands, and its overhead lies between theirs