ICGA Journal - Volume 21, issue 2

Article Type: Other

DOI: 10.3233/ICG-1998-21201

Citation: ICGA Journal, vol. 21, no. 2, pp. 73-74, 1998

Authors: Heinz, E.A.

Article Type: Research Article

Abstract: This article presents a new selective pruning technique for alpha-beta based game-tree search in computer chess, called extended futility pruning . It builds on ideas of both razoring and normal futility pruning at frontier nodes (depth = 1), and it cuts complete branches of the search tree at pre-frontier nodes (depth = 2) according to solely static criteria at the respective nodes. Hence, extended futility pruning performs true forward pruning. Although extended futility pruning is theoretically unsound, extensive experiments with our master-strength chess program DARK THOUGHT show that it works markedly well in practice. Even at fixed search …depths, extended futility pruning exhibits hardly any loss of tactical strength while shrinking the search trees by 10 to 20 percent on average as compared with normal futility pruning. Moreover, extended futility pruning combines nicely with a conservatively limited variation of razoring. It reduces the search trees at fixed search depths of more than 10 plies by an additional 5 to 15 percent on average. Finally, we have observed that the presented pruning schemes scale very well with the search depth, and reap ever more benefits at higher depths. Show more

DOI: 10.3233/ICG-1998-21202

Citation: ICGA Journal, vol. 21, no. 2, pp. 75-83, 1998

Authors: Baxter, J. | Tridgell, A. | Weaver, L

Article Type: Research Article

Abstract: This paper deals with the problem of automatically learning evaluation-function parameters. In particular, we describe some experiments in which our chess program KNIGHT CAP learnt the parameters of its evaluation function using a combination of temporal difference learning and on-line play on FICS (Free Internet Chess Server) and ICC (Internet Chess Club). The main success reported is that KNIGHT CAP went from a blitz rating of 1650 to a blitz rating of 2150 in just three days and 308 games. We provide details of our learning algorithm, details of KNIGHT CAP , and some reasons for KNIGHT …CAP ’S rapid improvement in playing strength. Show more

DOI: 10.3233/ICG-1998-21203

Citation: ICGA Journal, vol. 21, no. 2, pp. 84-99, 1998

Authors: Finkelstein, L. | Markovitch, S.

Article Type: Research Article

Abstract: Human chess players do not perceive a position as a static entity, but as a collection of potential actions. Moreover, they seem to be able to follow promising moves without considering all the alternatives. This contribution investigates the possibility of incorporating such capabilities into chess programs. We describe a methodology and a language for representing move patterns . A move pattern is a structure consisting of a board pattern and a move that can be applied in that pattern. Move patterns are used for selecting promising branches of a search tree, hence allowing for a narrower and therefore deeper search …tree. Move patterns are learned during training games and are stored in a hierarchical structure to enable fast retrieval. The paper describes algorithms for learning, storing, retrieving, and using the move patterns. Show more

DOI: 10.3233/ICG-1998-21204

Citation: ICGA Journal, vol. 21, no. 2, pp. 100-119, 1998

Article Type: Other

DOI: 10.3233/ICG-1998-21205

Citation: ICGA Journal, vol. 21, no. 2, pp. 120-120, 1998

Article Type: Other

DOI: 10.3233/ICG-1998-21206

Citation: ICGA Journal, vol. 21, no. 2, pp. 121-121, 1998

Authors: van den Herik, H. Jaap

Article Type: Other

DOI: 10.3233/ICG-1998-21207

Citation: ICGA Journal, vol. 21, no. 2, pp. 122-124, 1998

Authors: van den Herik, H.J.

Article Type: Other

DOI: 10.3233/ICG-1998-21208

Citation: ICGA Journal, vol. 21, no. 2, pp. 125-125, 1998

Authors: Friedel, F.

Article Type: Other

DOI: 10.3233/ICG-1998-21209

Citation: ICGA Journal, vol. 21, no. 2, pp. 126-130, 1998

Authors: Althöfer, I.

Article Type: Research Article

DOI: 10.3233/ICG-1998-21210

Citation: ICGA Journal, vol. 21, no. 2, pp. 131-134, 1998

Authors: Grimbergen, Reijer | Iida, Hiroyuki

Article Type: Other

DOI: 10.3233/ICG-1998-21211

Citation: ICGA Journal, vol. 21, no. 2, pp. 135-137, 1998

Article Type: Other

DOI: 10.3233/ICG-1998-21212

Citation: ICGA Journal, vol. 21, no. 2, pp. 138-138, 1998

Article Type: Other

DOI: 10.3233/ICG-1998-21213

Citation: ICGA Journal, vol. 21, no. 2, pp. 138-138, 1998

Article Type: Other

DOI: 10.3233/ICG-1998-21214

Citation: ICGA Journal, vol. 21, no. 2, pp. 139-141, 1998

Article Type: Other

DOI: 10.3233/ICG-1998-21215

Citation: ICGA Journal, vol. 21, no. 2, pp. 142-142, 1998

Authors: Karlsson, T.

Article Type: Other

DOI: 10.3233/ICG-1998-21216

Citation: ICGA Journal, vol. 21, no. 2, pp. 143-143, 1998