Re: [computer-go] Hash tables

2009-07-07 Thread Peter Drake
On Jul 6, 2009, at 10:09 PM, Peter Drake wrote: I suppose I could also include first child / next sibling pointers. I wouldn't actually use them when performing playouts, but they would greatly speed up the mark phase of marking and sweeping. Hmm. That would work for a tree, but this is a

Re: [computer-go] Really basic question

2009-07-07 Thread Oliver Lewis
Although the number of games explored is very limited relative to the total number of possible games, those games are in some sense representative of what happens if you start with a particular move. That's why they can help to create a ranking that tells you something about which moves are

Re: [computer-go] Really basic question

2009-07-07 Thread Magnus Persson
Quoting Oliver Lewis ojfle...@gmail.com: Others on this list have reported in the past that the randomness is actually very important. Playouts that are very heavy, no matter how clever they are, actually reduce the performance because they narrow the number of games too much. I would like

Re: [computer-go] Really basic question

2009-07-07 Thread Heikki Levanto
On Tue, Jul 07, 2009 at 09:16:25AM +0200, Oliver Lewis wrote: You should also read up on the all moves as first (AMAF) technique. This is even more surprising because it attributes the outcome of a random game to every move of that colour during the random game, as if that was the move that

Re: [computer-go] Really basic question

2009-07-07 Thread Christian Nentwich
Fred, others have already indicated that you are missing the tree part of Monte Carlo Tree Search, but there is something else to add. If you run uniform random playouts on an empty 9x9 board, let's say a million of them for each point, you will see a probability distribution emerging that

[computer-go] Experimentation (was: Really basic question)

2009-07-07 Thread Christian Nentwich
The problem I think is to find a good tradeoff between heavyness and speed. In my test with Valkyria vs Fuego, Valkyria is superior when the number of playouts are the same. But Fuego can play 5 times more playouts per second on the hardware that results in Fuego being slightly stronger than

Re: [computer-go] Experimentation

2009-07-07 Thread Darren Cook
What is the motivation in this? I cannot conceive of any good reason for running an experiment this way, so I would be interested in opinions. It seems to me that making algorithms heavier and then demonstrating that they are stronger with the same number of playouts misses the point - why

Re: [computer-go] Experimentation

2009-07-07 Thread Christian Nentwich
Darren Cook wrote: seems to me that making algorithms heavier and then demonstrating that they are stronger with the same number of playouts misses the point - why would one not run an experiment under the same time conditions instead? * The heavier algorithm might be unoptimized; That

Re: [computer-go] Experimentation

2009-07-07 Thread Darren Cook
* The scaling behaviour might be different. E.g. if fuego and Valkyria are both run with 10 times more playouts the win rate might change I am not sure I follow this argument. How do you intend to prove that, unless you run the algorithms with 10 times more playouts? I think showing

Re: [computer-go] Experimentation

2009-07-07 Thread Magnus Persson
Quoting Darren Cook dar...@dcook.org: * The scaling behavior might be different. E.g. if Fuego and Valkyria are both run with 10 times more playouts the win rate might change. Just to dismiss an algorithm that loses at time limits that happen to suit rapid testing on today's hardware could mean

Re: [computer-go] Scoring - step function or sigmoid function?

2009-07-07 Thread Stefan Kaitschick
My conclusion was that the winning percentage is more than just an estimate of how likely the player is to win. It is in fact a crude estimator of the final score. Going back to your original comment, when choosing between move A that leads to a 0.5pt win, and move B that leads to a 100pt win,

Re: [computer-go] Really basic question

2009-07-07 Thread Don Dailey
On Tue, Jul 7, 2009 at 3:49 AM, Magnus Persson magnus.pers...@phmp.sewrote: Quoting Oliver Lewis ojfle...@gmail.com: Others on this list have reported in the past that the randomness is actually very important. Playouts that are very heavy, no matter how clever they are, actually reduce

RE: [computer-go] Experimentation (was: Really basic question)

2009-07-07 Thread David Fotland
Experiments with equal playouts are much easier to control to get accurate results. David What is the motivation in this? I cannot conceive of any good reason for running an experiment this way, so I would be interested in opinions. It seems to me that making algorithms heavier and then

[computer-go] Anchor on cgos 19x19?

2009-07-07 Thread David Fotland
Many Faces has won almost 100 games in a row to get a high rating, but without an anchor, that rating is probably not accurate. Is anyone willing to put up an anchor or a stronger program that has lots of games and a stable rating? David ___

Re: [computer-go] Experimentation (was: Really basic question)

2009-07-07 Thread Don Dailey
On Tue, Jul 7, 2009 at 6:31 AM, Christian Nentwich christ...@modeltwozero.com wrote: The problem I think is to find a good tradeoff between heavyness and speed. In my test with Valkyria vs Fuego, Valkyria is superior when the number of playouts are the same. But Fuego can play 5 times more

Re: [computer-go] Experimentation

2009-07-07 Thread Christian Nentwich
Don, I see where this argument comes from, but you are not taking it to its conclusion. Unless you can, in the end, show that your algorithm can outperform another one with the same time limit, you have not proved that it is an advance. That is why tournaments are played with time limits,

Re: [computer-go] Experimentation

2009-07-07 Thread Christian Nentwich
Magnus, along the lines of the argument I am trying to make: did you try your experiments with time limits from 30 seconds per game to five minutes per game (say), rather than playouts? Using gogui-twogtp this is relatively easy to achieve. I am obviously not associated with Fuego, but I

Re: [computer-go] Experimentation

2009-07-07 Thread Hellwig Geisse
On Tue, 2009-07-07 at 17:09 +0100, Christian Nentwich wrote: [..] Unless you can, in the end, show that your algorithm can outperform another one with the same time limit, you have not proved that it is an advance. That is why tournaments are played with time limits, not limits on the

Re: [computer-go] Really basic question

2009-07-07 Thread terry mcintyre
megasnippage of Don's post: Adding an additional order of magnitude more time to the search [ in Rybka] is not going to change the basic misconception if the evaluation just doesn't understand the position. [ Don suggests that this applies even more so to Go ] Amen! We've covered variants of

[computer-go] Experimentation

2009-07-07 Thread Brian Sheppard
If your program is limited by memory size, then it makes sense to limit experiments by trial count. Running on your development computer, you might be limited by clock time. Running on competition hardware, you might not be. ___ computer-go mailing

Re: [computer-go] Experimentation

2009-07-07 Thread Gian-Carlo Pascutto
Brian Sheppard wrote: Running on your development computer, you might be limited by clock time. Running on competition hardware, you might not be. Only if the algorithm doesn't scale. Which makes it uninteresting to begin with. -- GCP ___

Re: [computer-go] Experimentation

2009-07-07 Thread Don Dailey
On Tue, Jul 7, 2009 at 12:09 PM, Christian Nentwich christ...@modeltwozero.com wrote: Don, I see where this argument comes from, but you are not taking it to its conclusion. Unless you can, in the end, show that your algorithm can outperform another one with the same time limit, you have

[computer-go] Experimentation

2009-07-07 Thread Brian Sheppard
Running on your development computer, you might be limited by clock time. Running on competition hardware, you might not be. Only if the algorithm doesn't scale. Perhaps there is a misunderstanding? A scalable algorithm is limited by the hardware it runs on. The limit may differ when you

Re: [computer-go] Experimentation

2009-07-07 Thread Magnus Persson
I have not used time exactly to match up Valkyria and Fuego. But also with fixed numbers of simulations one can match them up closely in processor time. And then I do that Valkyria wins something like 41-45% of the time. I never intentionally designed Valkyria to work well small number of

Re: [computer-go] Experimentation

2009-07-07 Thread terry mcintyre
Digesting Don's remarks, it seems that a reasonable method would start with equal numbers of simulations. It could then proceed to try various optimizations, and compare algorithms which use equal time. It makes perfect sense for the ultimate goal to be better performance using the same time

Re: [computer-go] Experimentation

2009-07-07 Thread steve uurtamo
something i've played with a little bit: only look at algorithms with the following property: * they every so often update an in-memory score for each board position. you can then run a timing loop around this and just make the highest-scoring valid move the play. you can use a signal handler

Re: [computer-go] Scoring - step function or sigmoid function?

2009-07-07 Thread Darren Cook
MC bots play handicap games poorly. ... So my suggestion would be to pretend that there is a komi that almost compensates the handicap. The same ideas has been suggested before [1]. The counter comments were mostly that hard to get right or tried that briefly and it didn't work well. Darren