[computer-go] A new pairing system idea for CGOS

[Don Dailey]

Thanks for the suggestion Matt.   I will consideration to all the idea
that have been proposed. 

- Don


On Thu, 2006-10-05 at 23:30 -0500, Matt Gokey wrote:
> Hi all.
> 
> There has been a number of suggestions for a pairing algorithm for CGOS 
> which all seem to have their pros and cons.  I am offering some thoughts 
> on this topic and a simple (perhaps naive) pairing technique to add to 
> the discussion.
> 
> First, Don is excited about the potential for the swiss tournament style 
> system.  I don't think it really fits the CGOS goals that well, but I 
> must admit I don't understand it completely nor exactly how he plans to 
> use it.  CGOS is not really a tournament based system, it's an automated 
> and continuous running game server to make it easy for computer go 
> engines to play against other computer go engines and rate them to 
> "understand" their relative strengths.  I don't have a program playing 
> on it yet, but I think it is a great thing to have available for 
> computer-go.  What Don has done with this including sticking to 
> principles such as tromp-taylor rules to make it fully automated is 
> wonderful.  Changing it to a tournament based system would seem to 
> complicate it IMO.
> 
> Anyway, the goals of the new pairing system for CGOS as I have heard 
> them and understand them are:
> 1. To have each engine play approximately the same number of games.
> 2. To pair engines of relative similar strength together more often than 
> those wildly different.
> 
> Pairing in rounds provides for the first goal.
> 
> How about this simple idea to provide for the second goal:
> 
> 1. Pick a random player A from the remaining available players.
> 2. Select a player B from the remaining available players using a 
> weighted random selection with the weight based on an inverse distance 
> formula between player A's rating and each remaining player's rating.
> 3. Repeat until all players are paired.  Odd man out.
> 4. Play all the games and update ratings.
> 5. Clear all pairings and go back to 1 for the next round.
> 
> In this way any player can play any other player, but pairings between 
> similar or closer strength players will be more probable.  The weight 
> formula could take many forms thus changing the probabilities of 
> dissimilar pairings and I don't know what the best one would be, but 
> conceptually this seems to be a straightforward way to achieve the 
> objectives which have been expressed.  KISS.  So fire away, how does 
> this sound and where are the holes?
> 
> Matt