Forum Archive : Programming

Search in Trees with Chance Nodes From:   Thomas Hauk Address:   hauk@cs.ualberta.ca Date:   26 February 2004 Subject:   Backgammon-related Thesis Forum:   rec.games.backgammon Google:   nobody-D0C503.23370425022004@news.telus.net I have recently finished my thesis, "Search in Trees with Chance Nodes". The thesis explored a new method for performing search in games which involve chance events. The main focus of interest was on backgammon, and I used the set of GNU Backgammon neural networks for performing evaluation of backgammon positions, while I implemented my own search routines. The search routines in question are the *-Minimax functions created by Bruce Ballard in 1983, dubbed Star1 and Star2. While the final results were not as spectacular as we would have hoped (mainly due to how the Gnubg NN works rather than inherent problems with the algorithms), the great hope is that the (first) real-world results I presented will renew interest in improving search in stochastic domains. Being a Master's thesis in Computing Science, it is not intended for a general audience, but if you have an interest in backgammon, or AI, there should be plenty there to chew on (mentally, that is). My thesis is available in PDF, PS and PS.gz formats at http://www.cs.ualberta.ca/~hauk/ Thanks again to the GNU Backgammon team (including anyone who felt I was wasting their time asking questions about the code!). It's not often one runs into a program that is so good, it can barely be improved. Kudos.   Did you find the information in this article useful?           Do you have any comments you'd like to add?

 

Programming

Adjusting to a weaker opponent  (Brian Sheppard, July 1997) 

Anticomputer positions  (Bill Taylor+, June 1998) 

BKG 9.8 vs. Villa  (Raccoon+, Aug 2006) 

BKG 9.8 vs. Villa  (Andreas Schneider, June 1992) 

BKG beats world champion  (Marty Storer, Sept 1991) 

Backgames  (David Montgomery+, June 1998) 

Blockading feature  (Sam Pottle+, Feb 1999) 

Board encoding for neural network  (Brian Sheppard, Feb 1997) 

Bot weaknesses  (Douglas Zare, Mar 2003) 

Building and training a neural-net player  (Brian Sheppard, Aug 1998) 

How to count plies?  (Chuck Bower+, Jan 2004) 

How to count plies?  (tanglebear+, Mar 2003) 

Ideas for improving computer play  (David Montgomery, Feb 1994) 

Ideas on computer players  (Brian Sheppard, Feb 1997) 

Introduction  (Gareth McCaughan, Oct 1994) 

Measuring Difficulty  (John Robson+, Feb 2005) 

Methods of encoding positions  (Gary Wong, Jan 2001) 

N-ply algorithm  (eXtreme Gammon, Jan 2011) 

Neural net questions  (Brian Sheppard, Mar 1999) 

Pruning the list of moves  (David Montgomery+, Feb 1994) 

Search in Trees with Chance Nodes  (Thomas Hauk, Feb 2004) 

Source code  (Gary Wong, Dec 1999) 

TD-Gammon vs. Robertie  (David Escoffery, June 1992) 

Training for different gammon values  (Gerry Tesauro, Feb 1996) 

Training neural nets  (Walter Trice, Nov 2000) 

Variance reduction in races  (David Montgomery+, Dec 1998) 

Variance reduction of rollouts  (Michael J. Zehr+, Aug 1998) 

Variance reduction of rollouts  (Jim Williams, June 1997) 

What is a "neural net"?  (Gary Wong, Oct 1998) 

Writing a backgammon program  (Gary Wong, Jan 1999) 

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