Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Stefan Kaitschick
Maybe I should ask first, for clarity sake, is MCTS performance in handicap games currently a problem? Mark Yes, it's a big problem. And thats not a matter of opinion. MC bots, leading a game by a large margin, will give away their advantage lighly except for the last half point. Even on a

Re: [computer-go] Monte-Carlo Simulation Balancing

2009-08-13 Thread Isaac Deutsch
I admit I had trouble understanding the details of the paper. What I think is the biggest problem for applying this to bigger (up to 19x19) games is that you somehow need access to the true value of a move, i.e. it's a win or a loss. On the 5x5 board they used, this might be approximated

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Tapani Raiko
I don't think the komi should be adjusted. Instead: Wouldn't random passing by black during the playouts model black making mistakes much more accurately? The number of random passes should be adjusted such that the playouts are close to 50/50. Adjusting the komi would make black play greedily,

Re: [computer-go] Monte-Carlo Simulation Balancing

2009-08-13 Thread Michael Williams
In future papers they should avoid using a strong authority like Fuego for the training and instead force it to learn from a naive uniform random playout policy (with 100x or 1000x more playouts) and then build on that with an iterative approach (as was suggested in the paper). I also had

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Hideki Kato
I'd like to say that the problem comes from the fact the model of the opponent in the simulations is not enough accurate in MCTS flamework. So, the solution is to make the model being more precise but this has practically no sense. What is Komi or handicap? Since W is stronger than B, W must

Re: [computer-go] Monte-Carlo Simulation Balancing

2009-08-13 Thread Jason House
A web search turned up a 2 page and an 8 page version. I read the short one. I agree that it's promising work that requires some follow- up research. Now that you've read it so many times, what excites you about it? Can you envision a way to scale it to larger patterns and boards on modern

[computer-go] Monte-Carlo Simulation Balancing

2009-08-13 Thread Brian Sheppard
Is anyone (besides the authors) doing research based on this? Well, Pebbles does apply reinforcement learning (RL) to improve its playout policy. But not in the manner described in that paper. There are practical obstacles to directly applying that paper. To directly apply that paper, you must

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Don Dailey
This idea makes much more sense to me than adjusting komi does.At least it's an attempt at opponent modeling, which is the actual problem that should be addressed. Whether it will actually work is something that could be tested. Another similar idea is not to pass but to play some

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Don Dailey
On Thu, Aug 13, 2009 at 1:39 AM, Christoph Birk b...@ociw.edu wrote: On Aug 12, 2009, at 3:43 PM, Don Dailey wrote: I believe the only thing wrong with the current MCTS strategy is that you cannot get a statistical meaningful number of samples when almost all games are won or lost.You

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread terry mcintyre
One reason dynamic komi seems a bit odd is that the numbers are pulled out of thin air. Why should the komi be X instead of Y? When should the value be changed? Going back to the original thought experiment: the komi at the start of the game should reflect the expert assessment of how far

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Isaac Deutsch
With crazystone-like playouts, you can just put noise over the possibilites. the more noise, the more random the playout is, which is weaker. The best move in the tree is then the one that requires the least amount of noise for the other player to reach 50% win chance if behind, or the one

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Stefan Kaitschick
Modeling the opponents mistakes is indeed an alternative to introducing komi. But it would have to be a lot more exact than simply rolling the dice or skipping a move here and there. Successful opponent modeling would implement the overplay school of thought - playing tactically refutable

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Don Dailey
There is one crude way to measure goal compatibility. See if you can make the same move work with different komi.If I'm on the east coast of the US traveling to the west coast, I will probably start off on the same road regardless of whether I'm going to Seattle or San Diego.If the same

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Don Dailey
2009/8/13 Stefan Kaitschick stefan.kaitsch...@hamburg.de Modeling the opponents mistakes is indeed an alternative to introducing komi. But it would have to be a lot more exact than simply rolling the dice or skipping a move here and there. Successful opponent modeling would implement the

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread terry mcintyre
The dynamic komi is perhaps a misnomer; it's by accident that changing komi reflects something which we do want to measure, namely the predicted score. An algorithm which does not make use of the predicted score would not make use of all available information. On a 19x19 board, it is common

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread Don Dailey
2009/8/13 terry mcintyre terrymcint...@yahoo.com The dynamic komi is perhaps a misnomer; it's by accident that changing komi reflects something which we do want to measure, namely the predicted score. An algorithm which does not make use of the predicted score would not make use of all

Re: [computer-go] Dynamic komi at high handicaps

2009-08-13 Thread terry mcintyre
I have never heard a pro say I estimate my chances of winning this game to be 50.3%, but you will hear black is ahead by 3 points or white wins by 1/2 point. -- they'll make this evaluation based on the alternation of equally competent play. Terry McIntyre terrymcint...@yahoo.com “We hang

Re: [computer-go] Monte-Carlo Simulation Balancing

2009-08-13 Thread Olivier Teytaud
. Pebbles has a Mogo playout design, where you check for patterns only around the last move (or two). In MoGo, it's not only around the last move (at least with some probability and when there are empty spaces in the board); this is the fill board modification. (this provides a big

[computer-go] Monte-Carlo Simulation Balancing

2009-08-13 Thread Brian Sheppard
. Pebbles has a Mogo playout design, where you check for patterns only around the last move (or two). In MoGo, it's not only around the last move (at least with some probability and when there are empty spaces in the board); this is the fill board modification. Just to clarify: I was not

Re: [computer-go] Monte-Carlo Simulation Balancing

2009-08-13 Thread Olivier Teytaud
Just to clarify: I was not saying that Mogo's policy consisted *solely* of looking for patterns around the last move. Merely that it does not look for patterns around *every* point, which other playout policies (e.g., CrazyStone, if I understand Remi's papers correctly) appear to do. The RL

[computer-go] Heavier playouts

2009-08-13 Thread David Fotland
A couple of weeks ago I made the playouts slightly heavier by adding a few 2-liberty local rules. It made a big difference in the program's strength (from strong 3 kyu to weak 1 kyu). www.gokgs.com/servlet/graph/ManyFaces-en_US.png David ___

Re: [computer-go] Heavier playouts

2009-08-13 Thread Robert Jasiek
David Fotland wrote: made the playouts slightly heavier by adding a few 2-liberty local rules. What does heavier mean here and could you please give an example of such a rule? Do you have an understanding why they make your program stronger? -- robert jasiek

RE: [computer-go] Heavier playouts

2009-08-13 Thread David Fotland
Heavier means more analysis in the playouts about what move to make - less pure random. I don't understand why its stronger, but I'm happy with the result. Playouts are pretty much try something and test it. David -Original Message- From: computer-go-boun...@computer-go.org

[computer-go] Re: Heavier playouts

2009-08-13 Thread Hideki Kato
David Fotland: 091c01ca1c4f$9dea69e0$d9bf3d...@com: A couple of weeks ago I made the playouts slightly heavier by adding a few 2-liberty local rules. It made a big difference in the program's strength (from strong 3 kyu to weak 1 kyu). www.gokgs.com/servlet/graph/ManyFaces-en_US.png Is this

RE: [computer-go] Re: Heavier playouts

2009-08-13 Thread David Fotland
Works for me. It's the rank graph. You can also get it on KGS, user info for ManyFaces -Original Message- From: computer-go-boun...@computer-go.org [mailto:computer-go- boun...@computer-go.org] On Behalf Of Hideki Kato Sent: Thursday, August 13, 2009 9:42 PM To: computer-go