Collaborative Computer Personalities in the Game of Chess DCU By Ai dan Haran B.Sc. A Dissertation Presented in Fulfilment of the Requirements for the M.Sc. Degree Supervisor: Dr. David Sinclair School of Computer Applications DCU August 2002 Declaration I hereby certify that this material, which I now submit for assessment on the programme of study leading to the award of Masters in Computer Applications is entirely my own work and has not been taken from the work of others save and to the extent that such work has been cited and acknowledged within the text of my work. Signed: ID No.: Date: ii Acknowledgements I would like to thank my supervisor, Dr David Sinclair, for his help and guidance during my research and write-up. Thanks to all my fellow post-grads who make the time pass so quickly especially Paul Browne, Kieran McDonald, Jer Hayes, Thomas Sodring, Jiamin Ye, Cathal Gurrin, Dr Wu Hai and Dr Hyowon Lee. Best of luck to all of you who are still working on your PhD degrees. I would especially like to thank my parents and family for their support and assistance during my extended stay in college. Thanks ! REFERENCE Table of Contents Chapter 1 Introduction..............................................................................................1 1.1 Importance of Chess in Artificial Intelligence Research.......................... 1 1.2 Purpose of Research...........................................................................,3 Chapter 2 How Computers Play Chess................................................................ 5 2.1 Viewing Chess as a Game T re e ..............................................................5 2.2 Static Board Evaluation Function............................................................ 9 2.3 Sequential Tree Search................................................... ...................... 12 2.3.1 Minimax Algorithm ................................................................... 12 2.3.2 Alpha-Beta Algorithm .............................................................. 16 2.3.3 Transposition T able................................................................. 18 2.3.4 Quiescence Search................................................................ 19 2.3.5 Iterative Deepening................................................................... 20 2.4 Problems with Current Computer Chess Techniques............. ........ 21 2.4.1 Trade-off between Knowledge and Search......................... 21 2.4.2 Problem of Knowledge Acquisition....................................... 23 Chapter 3 Kasparov versus The World............................................................... 26 3.1 Background of Contest........................................................................ 26 3.2 Details and Rules of Contest................................................................. 27 3.3 The M atch.............................................................................................. 30 3.4 Sum mary.................................................................................................34 Chapter 4 Collaborative Computer Personalities in Computer Chess........ 36 4.1 Possible Advantages of Collaboration............................................... 38 4.2 Possible Disadvantages of Collaboration.......................................... 39 4.3 Constructing Chess Personalities...................................................... 40 4.4 Designing Multiple Personalities Solution Methods (MPSMs)........ 42 4.4.1 Limitations Imposed upon MPSMs..........................................44 4.5 Sum mary..................................................................................................46 Chapter 5 Test System 47 5.1 Process Control Used by Test System ............................................... .47 5.2 Distribution of Processes........................................................................49 5.2.1 Aglets Overview.........................................................................50 5.2.2 Design of Aglet System ........................ .................................. 51 5.3 Chess Engine..............................................................................................59 5.3.1 Search Algorithm .................................................................... 60 5.3.2 Evaluation Function.................................................................60 5.4 Critique of Test System ........................................................................... 63 Chapter 6 Results and Analysis ............................... ............................................... 64 6.1 Construction of Test S e t.......................................................................... 64 6.2 Details of Test Personalities................................................................... 66 6.2.1 Normal Personality................................................................. 66 6.2.2 Aggressive Personality.................................. ....................... 71 6.2.3 Defensive Personality............................................................ 73 6.2.4 Semi-Open Personality.......................................................... 75 6.2.5 Positional Personality.................................... , ......................77 6.3 Arrangement of Teams and Personalities...............................................79 6.4 Initial Method of Point Assignment......................................................... 80 6.5 Description of MPSM 1 ....................................................................... 82 6.6 Description of MPSM 2 ........................................................................ 86 6.7 Problem of Draws and Endgames with Test System and Solution .. 88 6.8 Re-testing using Solution to Draws and Endgames Problem.......... 91 6.9 Description of MPSM 3 ..... .................................................................. 92 6.10 Description of MPSM 4 ........................................................................ 94 6.11 Horizon Effect en Masse Problem with MPSM 4 ......................................96 6.12 Solution to Horizon Effect en M asse........................................................97 6.13 Tests with Quiescence Search.................................................................98 6.14 Performance of Black as Single Player Team ......................................... 99 6.15 Analysis..................................................................................................... 102 Chapter 7 C o n clusion s............................................................................................ 105 7.1 Purpose of this Research...................................................................... 106 7.2 Summary of Results............................................................................. 107 7.3 Future W o rk ............................................................................................ 108 v References............................................................................................... ......................110 Appendix A FIDE Laws of Chess...............................................................................115 Appendix B Chess Notation....................................................................................... 123 Appendix C Test Set Opening Sequences............................................................... 127 Appendix D Test Results............................................................................................ 128 vi Abstract Computer chess has played a crucial role in Artificial Intelligence research since the creation of the modem computer. It has gained this prominent position due to the large domain that it encompasses, including psychology, philosophy and computer science. The new and innovative techniques initially created for computer chess have often been successfully transferred to other divergent research areas such as theorem provers and economic models. The progress achieved by computers in the game of chess has been illustrated by Deep Blue’s famous victory over Garry Kasparov in 1997. However, further improvements are required if more complex problems are to be solved. In 1999 the Kasparov versus the World match took place over the Internet. The match allowed chess players from around the world to collaborate in a single game of chess against the then world champion, Garry Kasparov. The game was closely fought with Kasparov coming out on top. One of the most surprising aspects of the contest was the high quality of play achieved by the World team. The World team consisted of players with varying skill and style of play, despite this they achieved a level of play that was considered better than any of its individual members. The purpose of this research is to investigate if collaboration by different players can be successfully transferred to the domain of computer chess. Chapter 1 Introduction 1.1 Importance of Chess in Artificial Intelligence Research Artificial Intelligence, simply referred to as AI, is the area of research concerned with the creation of computational entities that exhibit intelligent behaviour. These entities would have the ability to perform difficult or unwanted tasks on our behalf. Since the inception of AI, fantastical ideas of the progress of AI have been made, such as the character of HAL in the film "2001: A Space Odyssey”. Unfortunately science fiction left reality far behind in the creation of intelligent entities. Progress in AI has been slow