Singular extensions
Singular extensions ( German "isolated extensions" , also One Reply Extensions or Singular Reply Extensions ) is a special programming technique called in computer chess in which forced moves are examined much more deeply than is given by the usual calculation depth.
history
This innovative idea was triggered by a game of computer chess that took place in 1986 at the 7th North American Computer Chess Championship (NACCC) . Organized by the Association for Computing Machinery (ACM) , it took place in Dallas . The two chess programs Bebe and Lachex clashed in an important game that decided who would come second behind the tournament winner Belle . A position arose in which there was a series of forced moves for both sides, i.e. those in which there was only one single “reasonable” answer. However, each of the two programs only calculated “stubbornly” up to its specified search depth. Because of the “horizon effect”, it was hidden from both of them for a long time who would emerge from the sequence of moves with a profit. This only changed when the end of the forced moves suddenly moved in front of the search horizon and both recognized that Bebe was now at a loss.
In a discussion by computer chess programmers, including Feng-hsiung Hsu and Tony Scherzer , under the impression of this event, Scherzer formulated the decisive idea, namely to analyze such isolated move sequences much deeper and always until the end of the forced moves, deliberately disregarding the preset search depth. This is how the Singular Extensions came about , which turned out to be a groundbreaking innovation in computer chess and which make a significant contribution to the playing strength of today's programs.
literature
- Dieter Steinwender , Frederic Friedel : Chess on the PC . Markt & Technik , Buch- und Software-Verlag GmbH, Haar near Munich, 1995, p. 93 and p. 478. ISBN 3-87791-522-1
- Thomas Anantharaman , Murray Campbell , Feng-hsiung Hsu : Singular extensions - Adding Selectivity to Brute-Force Searching. AAAI Spring Symposium, Computer Game Playing, 1988, pp. 8-13. Also in ICCA Journal, Vol. 11, No. 4, and in Artificial Intelligence, Vol. 43, No. 1, pp. 99-109 1990, ISSN 0004-3702
Individual evidence
- ↑ ChessProgramming Wiki accessed on November 24, 2017
- ↑ Feng-hsiung Hsu : Behind Deep Blue - Building the Computer that Defeated the World Chess Champion. Princeton University Press , 2002, pp. 54-55, ISBN 0-691-09065-3