Crafty and Recent Developments in Computer Chess

Robert M. Hyatt, Associate Professor
Department of Computer and Information Sciences
The University of Alabama at Birmingham
hyatt@redmont1.cis.uab.edu

Abstract

Professor Hyatt will describe his highly acclaimed program Crafty (ICS rating 2491), which incorporates many recent advances in computer chess technology. These advances include:

  1. using parallel machines to search deeper into the game tree,
  2. improving the chess knowledge contained in the program so that it plays better positional and goal-oriented chess,
  3. improving search strategies so that the program analyzes deeper in selected positions that require additional search, and
  4. new fast algorithms for move generation.

Computer chess expert Professor Hyatt is the author of Cray Blitz, World Computer Champion from 1983 to 1989, developed jointly with Lawrence Livermore Laboratory and Cray Research, Inc.

Schedule

Wednesday, December 13, 1995
11am - Talk to general computer science audience
2pm - Specialized technical talk to computer chess seminar

Location

Both talks in ECS Room 210i (CSEE conference room), UMBC
Everyone is welcome to both events. Directions to UMBC.

Hosts

Alan T. Sherman and James Mayfield
CMSC-791 Graduate Seminar in Computer Chess
Department of Computer Science and Electrical Engineering
UMBC

This event is held in cooperation with the UMBC Chess Club.

Kasparov vs. Deep Blue

In February 1996, World Chess Champion Gary Kasparov will play IBM's Deep Blue in Philadelphia.

Notes

In reflecting on the success of Crafty, Professor Hyatt stressed the importance of parallel search, selective-deepening search, null-move heuristic, transposition tables, move-ordering, bit-board data structures, and the significant feedback he received from playing thousands of games on the ICC. Paradoxically, he also noted that the null-move heuristic, and transposition tables in parallel search, are also major sources of headaches. He described a new move-generation algorithm based on bit-board structures in which collections of moves are described by a single bitboard.

With his flexible Crafty source code, Professor Hyatt has been able to experiment with variations in this algorithms. He noted that what works for suites of chess problems does not always work well against ICC players. He advises against playing a program against itself because his experience shows that doing so inappropriately accentuates minor differences in program versions. Professor Hyatt believes strongly in testing ideas experimentally and gave examples of theoretical results from the literature that he was unable to verify experimentally. Also, he cautioned against the uncareful use of certain quantitative benchmarks: for example, a high number of nodes searched per second often is the result of a poor move-ordering heuristic (and not the sign of a strong progam).