Scout is an Alpha-Beta enhancement introduced by Judea Pearl in 1980^{[1]}^{[2]} . Scout was originally introduced by a recursive function called EVAL, with {MAX, MIN}-parameter. A boolean function called TEST was used to prove all siblings of the first brother were either below or equal to MAX so far, or above or equal to MIN. If a condition did not hold, a re-search was necessary to get the real new MAX or MIN value. This was essentially a null-window search, with the idea that the saved nodes of the TEST would outweigh re-searches in reasonable well-ordered search trees. Therefor Pearl expected Scout's superiority over Alpha-Beta in practical game trees, which was confirmed in 1985 by Rajjan Shinghal and Agata Muszycka-Jones^{[3]} .

^Judea Pearl (1980). Asymptotic Properties of Minimax Trees and Game-Searching Procedures. Artificial Intelligence, Vol. 14, No. 2, pp. 113-138. ISSN 0004-3702.

^Judea Pearl (1980). Scout: A Simple Game-Searching Algorithm with Proven Optimal Properties. Proceedings of the First Annual National Conference on Artificial Intelligence. Stanford. pdf

Home * Search * ScoutScoutis an Alpha-Beta enhancement introduced by Judea Pearl in 1980^{[1]}^{[2]}. Scout was originally introduced by a recursive function called EVAL, with {MAX, MIN}-parameter. A boolean function called TEST was used to prove all siblings of the first brother were either below or equal to MAX so far, or above or equal to MIN. If a condition did not hold, a re-search was necessary to get the real new MAX or MIN value. This was essentially a null-window search, with the idea that the saved nodes of the TEST would outweigh re-searches in reasonable well-ordered search trees. Therefor Pearl expected Scout's superiority over Alpha-Beta in practical game trees, which was confirmed in 1985 by Rajjan Shinghal and Agata Muszycka-Jones^{[3]}.^{[4]}## Table of Contents

## Enhancements

In 1983 Alexander Reinefeld turned Scout and Negamax with some fail-soft refinements into NegaScout^{[5]}. Already in 1982 Tony Marsland and Murray Campbell introduced PVS^{[6]}, based on Finkel's and Fishburn's routinePalphabeta^{[7]}, in Fishburn's 1981 Thesis^{[8]}calledCalphabeta, which in turn is similar to Judea Pearl's Scout.## See also

## External Links

## References

1980).Asymptotic Properties of Minimax Trees and Game-Searching Procedures.Artificial Intelligence, Vol. 14, No. 2, pp. 113-138. ISSN 0004-3702.1980).Scout: A Simple Game-Searching Algorithm with Proven Optimal Properties. Proceedings of the First Annual National Conference on Artificial Intelligence. Stanford. pdf1985).An empirical comparison of pruning strategies in game trees. IEEE Transactions on Systems, Man, and Cybernetics, Vol. 15, No. 31983).An Improvement to the Scout Tree-Search Algorithm.ICCA Journal, Vol. 6, No. 4, pp. 4-14. pdf1982).Parallel Search of Strongly Ordered Game Trees.ACM Computing Surveys, Vol. 14, No. 4, pdf1980).Parallel Alpha-Beta Search on Arachne.IEEE International Conference on Parallel Processing, pp. 235-243.1981).Analysis of Speedup in Distributed AlgorithmsPh.D. Thesis, University of Wisconsin-Madison, pdf,Calphabetaat page 167## What links here?

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