Fine-Grained Decision-Theoretic Search Control

Decision-theoretic control of search has previously used as its basic unit of com­ putation the generation and evaluation of a complete set of successors. Although this simplifies analysis. it results in some lost opportunities for pruning and satisficing. This paper therefore extends the analysis of the value of computation to cover in­ dividual successor evaluations. The ana­ lytic techniques used may prove useful for control of reasoning in more general set­ tings. A formula is developed for the ex­ pected value of a node, k of whose n suc­ cessors have been evaluated. This formula is used to estimate the value of expanding further successors. using a general formula for the value of a computation in game­ playing developed in earlier work. VVe ex­ hibit an improved version of the MGSS" algorithm . giYing empirical results for the game of Othello.