Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-09 Thread Michael Williams
I don't think this specific test had been done. But I'm assuming the result will be the same as previous tests: deviating from the pursuit of the the highest winning percentage leads to a degradation in strength. Brett Koonce wrote: Greetings from a lurker, Forgive me if I am talking out of

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-09 Thread jonas . kahn
Part of the problems stem from that playouts are weak, and more specifically notably weaker than the program itself. To begin with, a consequence is that most areas of the board are less clear than they should to playouts. This entails, I think, a preference for probable points against sure

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-09 Thread Olivier Teytaud
MC is playing most goal-directed (zielgerichtet in German) when the position is balanced or when the side of MC is slightly behind. However, when MC is clearly ahead or clearly behind it is playing rather lazy. At some point we were investigating that here, but only on small sets of games

[computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Ingo Althöfer
In the last few weeks I have been investigating Monte-Carlo (MC) game tree search on a rather abstract level. Especially I was able to reproduce the following behaviour of MC in a very clear model: MC is playing most goal-directed (zielgerichtet in German) when the position is balanced or when

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Gian-Carlo Pascutto
Especially I was able to reproduce the following behaviour of MC in a very clear model: MC is playing most goal-directed (zielgerichtet in German) when the position is balanced or when the side of MC is slightly behind. However, when MC is clearly ahead or clearly behind it is playing

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Don Dailey
I have some sense that it might be possible to slightly improve the playing strength with some dynamic komi scheme. However, I have also experimented quite a bit with various ways to do this and in each case I have been able to detect at least a slight weakening of play. That probably just

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Gian-Carlo Pascutto
Don Dailey wrote: That probably just means I have not stumbled on the right ideas or that I was not able to properly tune it. I would be delighted if someone was able to show us a workable scheme. I believe if something is found it will result in a very minor improvement, but that it will

[computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Ingo Althöfer
Hello Gian-Carlo, Gian-Carlo Pascutto wrote: There has been discussion here about dynamic komi to keep the winning rate close to 50%. As far as I saw there was no clear conclusion about whether that works. Some people argued that it should not exist and measuring objective winning rates is

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Don Dailey
On Mon, 2008-09-08 at 20:01 +0200, Gian-Carlo Pascutto wrote: Don Dailey wrote: That probably just means I have not stumbled on the right ideas or that I was not able to properly tune it. I would be delighted if someone was able to show us a workable scheme. I believe if something is

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread terry mcintyre
Interesting analysis, Don. Human players sometimes adhere to a simple policy: rich men don't pick fights. When one is objectively far ahead, one picks up the easy profits, and otherwise takes no risks. If moves A, B, and C are comparable risk-wise, one would prefer the more profitable of the

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Gian-Carlo Pascutto
Don Dailey wrote: Would a discrepancy on the amount of ELO gained or lost per handicap stone, when comparing MC bots to humans classical computers, be a good measure of the maximum possible improvement? Maybe. How could you accurately make such a measurement without thousands of games?

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Jason House
Actually your summary of what people do sounds exactly like what MC programs do, except for one point... MC programs don't differentiate moves by point value. They only look at winning rate. It's extremely tough to differentiate the one move sequence with 99.1% win rate when all other

Re: [computer-go] Goal-directedness of Monte-Carlo

2008-09-08 Thread Brett Koonce
Greetings from a lurker, Forgive me if I am talking out of my hat. It has been a long time since I have done any real coding. It seems most of the gains in MC/UCT come fairly quickly (or rather you can get within 50% of a good move guess with a few iterations). It would be interesting