A* with Lookahead Re-Evaluated

摘要: A* with lookahead (AL*) is a variant of that performs cost-bounded DFS from node when it generated. We show the original version AL* (AL*0) can, in some circumstances, fail to return an optimal solution because move pruning does. present two new versions, AL*1 and ELH, we prove always be correct give conditions which AL*0 guaranteed correct. In our experiments unit costs, was usually fastest version, but its advantage small. non-unit substantially outperforms both IDA*. also evaluate idea immediately expanding generated if has same f-value as parent. find doing so causes require more memory sometimes slows down.