Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: High branching factor games

Author: Ricardo Gibert

Date: 00:52:37 11/27/02

Go up one level in this thread


On November 27, 2002 at 00:34:45, Russell Reagan wrote:

>While I was at work tonight sitting at a computer, having nothing to do, I
>opened up the calculator program and started playing around with the branching
>factor for the game of go. I quickly realized that with such a large branching
>factor at each level (361 from the starting position), it's no wonder computer
>go programs play well below master level.
>
>Are there any games that have a high branching factor that computers are good
>at? The only games that I'm somewhat familiar with are chess, checkers, and go.
>Of those, it seems that the branching factor of the game largely determines how
>well computers play them. It seems that checkers with the lowest branching
>factor gives humans the hardest time, then chess, and then go with a much larger
>branching factor is not even in the same ballpark with the top humans.
>Does this relationship between branching factor and computer strength hold for
>other games?


Consider backgammon. Despite the element of chance, alpha beta is still
applicable. Also, because if the element of chance, the game has a very high
branching factor. You must account for all possible rolls in addition to all the
possible legal moves with the checkers.

The best backgammon programs play better than the best humans despite the high
branching factor. Humans do not really try to calculate all the possibilities,
so a program that searches just 3 ply ahead can outplay strong humans.

The other oddity about backgammon is that the use of neural nets has actually
been effective for evaluation. This contrasts with the results in chess.

If you are interested in reading more about this you can check out the following
site: http://www.bgsnowie.com/snowie/snowie.dhtml


>Or do some games break the pattern? If some games do break the
>pattern, why? Simplicity of the game? Magical shortcuts?
>
>Russell




This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.