[computer-go] 19x19 MC improvement

2008-01-23 Thread Hiroshi Yamashita

My program Aya637_4CPU is top on 19x19 CGOS now.
It is temporary, but I'm so happy!
Please don't run full power MoGo, Crazy Stone and Leela :-)

My main improvement was

1. Do not move dead stones.
Before doing playout, Aya does string capture search up to 7 plies(ladders
are extended). And set the probability of dead stones's liberty to 1/1.
This changed winning rate 0.17 to 0.33 (both are 200 games, 4po
against GnuGo 3.7.10) But in 9x9, this method changed nothing.
There is no ladder search in playout.

2. Change UCT exploration parameter

 exp_param = sqrt(2.0);
 uct = exp_param * sqrt( log(sum of all children playout) /
   (number of child playout) );
 uct_value = (child winning rate) + uct;

I changed exp_param sqrt(2.0) to sqrt(0.1).
This changed winning rate 0.10(660 games) to 0.22(140 games).
(1po, against GnuGo 3.7.10)
I was surprised such a small parameter change made big difference.

AyaMC's sytle is similar to Crazy Stone.
- progressive windening.
- pattern is only 3x3 from 1 professional player's game.
Uct code is like this, http://www.yss-aya.com/uct_aya_e.cpp
In 1po of the root initial position, 11 nodes are created,
and 18 candidates are searched

Regards,
Hiroshi Yamashita

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Re: [computer-go] Is MC-UCT really scalable ... is a troll

2008-01-23 Thread Alain Baeckeroot
Le mercredi 23 janvier 2008, ivan dubois a écrit :
 Hi Alain, 
 Sorry for being so insistant : 
You should browse the archive of the list, nearly the same discussion about
infinite and scalability happenned in 2007.

 
 No i just said that, unless i really understood nothing,  i read here from 
 well
 known competent persons that MC+UCT scales infinitely , and would reach 
 perfect
 play with infinite computational resources, and this is theoretically proven
 (which is not the case for classical program like our beloved GNU Go).
 
 This is absolutely true. Now this can also be said for a mini-max solver (my 
 point).
Don Dailey answered better than i could do, yes minimax also scales.

 
 So MC+UCT scales. (even against humans, martians, trolls, computers, gods 
 ... :)
 The conclusion does not follow. 
Ah ? Why not ? what is wrong in the reasonning ?
Should i think :
 It scales in theory so it does NOT scale in practice  ?

 The fact that it eventualy reaches perfect play with enough computing power
 does NOT mean that it scales well.
 Proof : A mini-max solver does reach perfect play with enough computing
 power BUT does not scale.
we dont have the same informations. For Minimax scales too, maybe the
improvement curve has a smaller slope than MC+UCT curve, but 
 
 Actualy, this theoritical property is a NESCESSARY condition for UCT
 to scale, but it is not a SUFFICIANT condition. The scalability of
 UCT has been proven by its outstanding results
From a pure logical point of vue 
 - Positive experiment are never a valid proof. They are only examples that
 makes one feel his theory is right.
 - Only counter example are proof that the theory is wrong.

 and Don's experiments, not by mathematics.   
Are you a troll ?

Alain

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RE: [computer-go] 19x19 MC improvement

2008-01-23 Thread David Fotland
Congratulations!  I'm really impressed with how fast the AyaMC improved.

Regards,

David

 -Original Message-
 From: [EMAIL PROTECTED] [mailto:computer-go-
 [EMAIL PROTECTED] On Behalf Of Hiroshi Yamashita
 Sent: Wednesday, January 23, 2008 12:12 AM
 To: computer-go
 Subject: [computer-go] 19x19 MC improvement
 
 My program Aya637_4CPU is top on 19x19 CGOS now.
 It is temporary, but I'm so happy!
 Please don't run full power MoGo, Crazy Stone and Leela :-)
 
 My main improvement was
 
 1. Do not move dead stones.
  Before doing playout, Aya does string capture search up to 7
 plies(ladders
  are extended). And set the probability of dead stones's liberty to
 1/1.
  This changed winning rate 0.17 to 0.33 (both are 200 games, 4po
  against GnuGo 3.7.10) But in 9x9, this method changed nothing.
  There is no ladder search in playout.
 
 2. Change UCT exploration parameter
 
   exp_param = sqrt(2.0);
   uct = exp_param * sqrt( log(sum of all children playout) /
 (number of child playout) );
   uct_value = (child winning rate) + uct;
 
  I changed exp_param sqrt(2.0) to sqrt(0.1).
  This changed winning rate 0.10(660 games) to 0.22(140 games).
  (1po, against GnuGo 3.7.10)
  I was surprised such a small parameter change made big difference.
 
 AyaMC's sytle is similar to Crazy Stone.
  - progressive windening.
  - pattern is only 3x3 from 1 professional player's game.
 Uct code is like this, http://www.yss-aya.com/uct_aya_e.cpp
 In 1po of the root initial position, 11 nodes are created,
  and 18 candidates are searched
 
 Regards,
 Hiroshi Yamashita
 
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Re: [computer-go] New scalability study : show uncertainty ?

2008-01-23 Thread Heikki Levanto
On Tue, Jan 22, 2008 at 09:51:11PM +0100, Alain Baeckeroot wrote:
 
 Le mardi 22 janvier 2008, Michael Williams a écrit :
   ...  perhaps only uniformly random playouts
   will scale to perfection.
  
  The reason that MC/UCT scales to perfection is because of the UCT part,
  not the MC (playout) part.  People seems to forget this a lot. 
  
 I agree on this _only_ if the UCT check all possible moves.
 If not one can be limited by the quality of the playout.

I think we may be confusing two different things here:

a) Using all possible moves in the playouts to evaluate a leaf in 
the UCT tree

b) Making the UCT search all possible moves in a position

These two are related, and I suspect often people use the same code for
listing the possible moves, so they tend to be the same in many programs.

Theoretically speaking, errors and bias in those two may well result in
different things. 

Most MC implementations (that I know of) avoid playing in one-point eyes.
That is alrady a deviation from all legal moves, but one that makes
perfectly good sense. Yet there is at least one exception, where playing into
an one-point eye can create a nakade, and kill a surrounding group... 

The selection of possible moves for a node in the UCT tree can be somewhat
slower, since it is not done nearly as often. Also, adding bad moves here
costs less than in the MC playout, since the UCT algorithm can see that they
will not lead anywhere, and not give them so much attention. 

I don't (yet?) have an UCT program, so I can not test this. Some day when I
have one, I will try to see how much it will help or hurt to try all legal
moves in the UCT portion... If someone else tries it before, let us all know!

  - Heikki


-- 
Heikki Levanto   In Murphy We Turst heikki (at) lsd (dot) dk

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Re: [computer-go] Is MC-UCT really scalable ... is a troll

2008-01-23 Thread Heikki Levanto
On Tue, Jan 22, 2008 at 05:17:48PM -0500, [EMAIL PROTECTED] wrote:
 
 Don't make too much of it. A 2-Dan program will play 2-Dan games, not just
 occasionally generate a 2-Dan move. :) 

True. Most weak beginners start the game with a move that is often seen in
professional play. Usually 3-3, 3-4, or 4-4.

-H


-- 
Heikki Levanto   In Murphy We Turst heikki (at) lsd (dot) dk

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Re: [computer-go] New scalability study : show uncertainty ?

2008-01-23 Thread Magnus Persson

Quoting Heikki Levanto [EMAIL PROTECTED]:


I agree on this _only_ if the UCT check all possible moves.
If not one can be limited by the quality of the playout.


I think we may be confusing two different things here:

a) Using all possible moves in the playouts to evaluate a leaf in
the UCT tree

b) Making the UCT search all possible moves in a position

These two are related, and I suspect often people use the same code for
listing the possible moves, so they tend to be the same in many programs.


Indeed, Valkyria, uses the same code to prune move in both the  
playouts and in the UCT-tree. This pruning is supposed to be 100% safe  
and applies to really bad and ugly moves. But it is really hard to do  
this right and I still find a lot of bugs of this kind. There is an  
advantage of using the same code in the UCT-part because when I watch  
the program play I can see mistakes in pruning which otherwise only  
would be unseen in the playouts.
In the latest version of Valkyria I make the exception that all moves  
are allowed if there is a ko fight, but I do not know if this is  
necessary at all.


-Magnus


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Re: [computer-go] New scalability study : show uncertainty ?

2008-01-23 Thread Heikki Levanto
On Wed, Jan 23, 2008 at 11:18:37AM +0100, Magnus Persson wrote:
 Indeed, Valkyria, uses the same code to prune move in both the  
 playouts and in the UCT-tree. This pruning is supposed to be 100% safe  
 and applies to really bad and ugly moves. 

But you still prune moves like filling a one-point eye. We know that there is
a pthological case where that indeed is a correct move. So Valkyria will
never converge to perfect play even with unlimited CPU power.


 But it is really hard to do  this right and I still find a lot of bugs of
 this kind. There is an  advantage of using the same code in the UCT-part
 because when I watch  the program play I can see mistakes in pruning which
 otherwise only  would be unseen in the playouts.

That is a valid point. Not to the theoretical discussion, but in practical
everyday life!

-H


-- 
Heikki Levanto   In Murphy We Turst heikki (at) lsd (dot) dk

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Re: [computer-go] New scalability study : show uncertainty ?

2008-01-23 Thread Magnus Persson

Quoting Heikki Levanto [EMAIL PROTECTED]:


But you still prune moves like filling a one-point eye. We know that there is
a pthological case where that indeed is a correct move. So Valkyria will
never converge to perfect play even with unlimited CPU power.


Yes, this is a known bug. :)

But, I will not fix it until I fixed some more urgent stuff (there is  
a very long list with higher priority). Also I feel that in the case  
of having a really strong program attempting perfect play with this  
bug as the only defect, the opponent has be extremely strong (or  
extremely lucky) to exploit it.
It might even not be possible to exploit aginst perfect play, because  
there may always be simpler ways to kill the group than making en eye  
and then fill it, alternatively let it live small and win on points.


MoGo is a good example of this. I think Valkyria has an edge against  
MoGo in many LD situations, but often MoGo just put territorial  
pressure on the groups leading to positions where the opponent either  
defends and loses on points or take a gamble, tenuki and die without  
tactical complications.


Magnus

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Re: [computer-go] scalability study - how close to perfection?

2008-01-23 Thread Nick Wedd
In message 
[EMAIL PROTECTED], Russ 
Williams [EMAIL PROTECTED] writes

A couple of technical nitpick questions:

On Jan 23, 2008 5:57 AM, David Fotland [EMAIL PROTECTED] wrote:

Since the komi contains a half point, there should be almost no ties,


How should there be almost no ties, instead of no ties, with the
half point in the komi?  (Or are you thinking of rulesets that award
half-points for seki situations and such?)


I know of no current rule set that assigns fractions of points in sekis, 
except to assign half a point to each player (which still results in an 
integer when you subtract one player's score from the other).  The SST 
(Ing) rules used to assign other fractions, but do not now do so.  I am 
not aware of a position under old SST rules such that the score 
difference could end up as exactly half a point, but there may be one.


However, some rule sets treat a game that enters an infinite cycle as a 
draw.  Current Chinese rules, as applied in Chinese professional events, 
are like this.


Nick


between two perfect players, one color will always win by half a point.


Is this actually provably true in the mathematical sense?  I agree it
has intuitive appeal, but on the face of it, it seems possible that a
perfectly played game could involve a fight over a big dragon,
resulting in a large score difference.  Perfect play on very small
boards doesn't always result in very close final scores, right?

Maybe part of the problem is I'm not 100% sure what perfect play
means for a player who loses. :)

cheers
russ
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Re: [computer-go] scalability study - how close to perfection?

2008-01-23 Thread Don Dailey
This bias was clear in 7x7 - I don't expect to see it here but I will
check when there are enough games at the upper levels.

- Don


David Fotland wrote:
 Since the komi contains a half point, there should be almost no ties, and
 between two perfect players, one color will always win by half a point.

 In your scalability study, as the number of playouts goes up, is there a
 bias toward one color winning more than half the games?

 If so, it would show that the programs are getting close to optimal play.

 If they are close to optimal play it would explain the scaling curve
 flattening out.

 David


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Re: [computer-go] New scalability study : show uncertainty ?

2008-01-23 Thread Jacques Basaldúa
I don't think only uniformly random playouts will scale to 
perfection because what we need for playouts is not just a simple 
average of final scores but a maximum (in negmax sense) score.  It 
should be the perfect evaluation function.


In other words, as MC simulation is a way to get an average of a 
value, when applying it to optimization problems we need some way to 
focus the simulations to the _peak_ in a state space.


It may be obvious when one consideres LD problems where the best move 
that leads to the maximum score (live) is only one and all other moves 
are bad.  At such positions it's almost no sense to simulate all legal 
moves with same probability.  So, IMHO, biasing simulations is not 
just a speed-up technique but is essentially important.


I agree, but what I meant about uniformly random playouts is the following:
What makes a move outstanding is being unpredictable. For a total novice,
playing at the key point of a bulky five may look like a touch of genius,
but when you learn a little, its an obvious move. The difference between a
5p and a 9p may be one or two moves nobody can predict (except a 9p). When 
we add knowledge we find the _ordinary_ good moves faster, we make weaker 
moves less probable, but that comes at a price, the price of making outstanding 
unpredictable moves less probable also. Perhaps that introduces a ceiling. 
I thought that was what you were also pointing. Of course, I don't claim 
uniformly random playouts are good, I just claim that they should (just as an 
infeasible theoretic argument) scale to perfection, of course that scaling 
doesn't have to be linear.


Jacques.


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Re: [computer-go] mathematical morphology

2008-01-23 Thread Erik van der Werf
On Jan 23, 2008 1:47 PM, Jacques Basaldúa [EMAIL PROTECTED] wrote:
 Erik van der Werf wrote:

  You may also be interested in my
  article on estimating potential territory

 I am. Can you post a link, please.

sure, it's all at:

http://erikvanderwerf.tengen.nl/publications.html

My thesis contains the latest version (see chapter 10); the original
article is mostly the same, and can be downloaded from:

http://erikvanderwerf.tengen.nl/pubdown/predicting_territory.pdf

Erik
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Re : [computer-go] Is MC-UCT really scalable ... is a troll

2008-01-23 Thread ivan dubois
Duhhh !

When I say a minimax solver, I mean a program witch returns a random move UNTIL 
it has completed its search, as I explained in a previous post. You all agreed 
this program didnt scale, so why are you saying, all of a sudden, that it DOES 
scale now !? 
Anyway I'm fed up with this discussion now, this is so too much pain and way 
too frustrating.


- Message d'origine 
De : Alain Baeckeroot [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 9h15mn 41s
Objet : Re: [computer-go] Is MC-UCT really scalable ... is a troll

Le mercredi 23 janvier 2008, ivan dubois a écrit :
 Hi Alain, 
 Sorry for being so insistant : 
You should browse the archive of the list, nearly the same discussion about
infinite and scalability happenned in 2007.

 
 No i just said that, unless i really understood nothing,  i read here from 
 well
 known competent persons that MC+UCT scales infinitely , and would reach 
 perfect
 play with infinite computational resources, and this is theoretically proven
 (which is not the case for classical program like our beloved GNU Go).
 
 This is absolutely true. Now this can also be said for a mini-max solver (my 
 point).
Don Dailey answered better than i could do, yes minimax also scales.

 
 So MC+UCT scales. (even against humans, martians, trolls, computers, gods 
 ... :)
 The conclusion does not follow. 
Ah ? Why not ? what is wrong in the reasonning ?
Should i think :
 It scales in theory so it does NOT scale in practice  ?

 The fact that it eventualy reaches perfect play with enough computing power
 does NOT mean that it scales well.
 Proof : A mini-max solver does reach perfect play with enough computing
 power BUT does not scale.
we dont have the same informations. For Minimax scales too, maybe the
improvement curve has a smaller slope than MC+UCT curve, but 
 
 Actualy, this theoritical property is a NESCESSARY condition for UCT
 to scale, but it is not a SUFFICIANT condition. The scalability of
 UCT has been proven by its outstanding results
From a pure logical point of vue 
- Positive experiment are never a valid proof. They are only examples that
makes one feel his theory is right.
- Only counter example are proof that the theory is wrong.

 and Don's experiments, not by mathematics.  
Are you a troll ?

Alain

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Re: Re : [computer-go] Is MC-UCT really scalable ... is a troll

2008-01-23 Thread Erik van der Werf
On Jan 23, 2008 2:45 PM, ivan dubois [EMAIL PROTECTED] wrote:
 When I say a minimax solver, I mean a program witch returns a random move 
 UNTIL it has completed its search, as I explained in a previous post.

A plain minimax solver (without enhancements like iterative deepening)
doesn't return anything until it has completed its search.

E.
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[computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread Harald Korneliussen
Ivan Dubois mentioned  the bent four in the corner shape as a
scalability killer, a situation where more playouts doesn't help
(much), because playouts systematically misevaluate it. As I
understand it, it could be corrected in the tree, but this is very
unlikely to happen until the very end of a game, by which time it may
be too late (Mogo having worked the entire game for that solid 0.5
win, which turns out to be a solid loss instead because of the
life-and-death misevaluation)

I recalled a KGS game of Mogo I'd looked at, where something very
similar happened, and with a little digging I found it again:

http://files.gokgs.com/games/2007/12/1/Ardalan-MoGoBot3.sgf

It turns out it's not the bent four shape, but I suspect it's
another such shape, where more playouts only confirm that these moves
aren't worth including into the tree, so that UCT catches them very
late, if ever.

If these situations can be reliably created by a human, then indeed
they put an upper limit on the real world scalability of a program.

If I should propose a hackish heuristic to deal with such situations,
this is it: At one point, when the problematic shape appeared, the
human must have done a move that to the computer seemed horribly bad.
Why did he do that? Doesn't he see that my shape is alive?. When
such situations occur, there are two possibilities:

1. The bot is playing a weaker human player, and the move is indeed bad.
2. The bot is playing a stronger human, and the move is actually good.

I think it may be a good idea to do something with the weighting in
these situations, so that the relevant moves are added to the tree. In
worst case, a lot of effort is wasted in proving a bad move bad - but
this should not be so serious, as the bad move will likely mean the
opponent has poor chances of winning anyway. In the best case, the
program's blunder is revealed after the fact. This may still leave
little chance of winning, (if the ld error was severe) but at least
the program's counting won't be off for the rest of the game. Since
today's programs don't care for winning margins, counting errors by
even a single point will spell disaster.

I believe this heurtistic would be cheap in terms of computational
cost, but hard to evaluate/tune. Self-play would not be very
effective...
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Re : Re : [computer-go] Is MC-UCT really scalable ... is a troll

2008-01-23 Thread ivan dubois
Ok, this is a special minimax solver. Call it the Ivan Dubois stupid minimax 
solver if you like. 
Anyway, its only purpose is to show that : 
Returns the best move when given enough time does NOT implie Is scalable 
in practice. 
I am very sad that this simple logic has no appeal to most people on this list.


- Message d'origine 
De : Erik van der Werf [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 15h21mn 37s
Objet : Re: Re : [computer-go] Is MC-UCT really scalable ... is a troll

On Jan 23, 2008 2:45 PM, ivan dubois [EMAIL PROTECTED] wrote:
 When I say a minimax solver, I mean a program witch returns a random move 
 UNTIL it has completed its search, as I explained in a previous post.

A plain minimax solver (without enhancements like iterative deepening)
doesn't return anything until it has completed its search.

E.
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Re: [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread Thomas Wolf

On Wed, 23 Jan 2008, Harald Korneliussen wrote:

 It turns out it's not the bent four shape, but I suspect it's
 another such shape, where more playouts only confirm that these moves
 aren't worth including into the tree, so that UCT catches them very
 late, if ever.

Just a quick note that an algorithm how to evaluate bent four like
positions with a minimax search is given in

http://lie.math.brocku.ca/twolf/papers/bent4.pdf

Thomas
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Re: [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread terry mcintyre
From: Harald Korneliussen [EMAIL PROTECTED]

I recalled a KGS game of Mogo I'd looked at, where something very similar 
happened, and with a little digging I found it again:

 http://files.gokgs.com/games/2007/12/1/Ardalan-MoGoBot3.sgf

Thanks for the example! That's the infamous square four - under any ruleset, 
it is absolutely and irrefutably dead.
 
Mogo mis-evaluated the group as alive, and believed the score to be a win by 
6.5. 

Since the group was dead, Mogo actually lost by 15.5 ( by area counting )

A white play at B1, move 195, was predictable. Had Mogo correctly anticipated 
and evaluated this nakade, it could have created a more robust shape.


Terry McIntyre [EMAIL PROTECTED] 








  

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Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread ivan dubois
Hello,

After thinking a bit more about it, I came to the conclusion that the so called 
Bent four in the corner shape, is not such a serious scalability killer (I 
like this term).
Nor is the situation that appears in your game.
Let me explain why : 
It would indeed be a scalability killer if Mogo was 100 % sure that some 
group is dead, when it is actually alive. However what happens is that it has 
some doubts about the situation. It may think for example it is 60 % alive and 
40 % dead. Of course it would be better for him to know the reality, but having 
some persistent doubt on it is not that much detrimental. For example if he has 
perfect information about the rest of the board, he will play perfectly on the 
rest of the board.  
I propose a chalenge to this list : Find a real scalability issue with Mogo or 
any other actual UCT program. (And prove it)

Ivan   


- Message d'origine 
De : Harald Korneliussen [EMAIL PROTECTED]
À : computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 15h31mn 20s
Objet : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies

Ivan Dubois mentioned  the bent four in the corner shape as a
scalability killer, a situation where more playouts doesn't help
(much), because playouts systematically misevaluate it. As I
understand it, it could be corrected in the tree, but this is very
unlikely to happen until the very end of a game, by which time it may
be too late (Mogo having worked the entire game for that solid 0.5
win, which turns out to be a solid loss instead because of the
life-and-death misevaluation)

I recalled a KGS game of Mogo I'd looked at, where something very
similar happened, and with a little digging I found it again:

http://files.gokgs.com/games/2007/12/1/Ardalan-MoGoBot3.sgf

It turns out it's not the bent four shape, but I suspect it's
another such shape, where more playouts only confirm that these moves
aren't worth including into the tree, so that UCT catches them very
late, if ever.

If these situations can be reliably created by a human, then indeed
they put an upper limit on the real world scalability of a program.

If I should propose a hackish heuristic to deal with such situations,
this is it: At one point, when the problematic shape appeared, the
human must have done a move that to the computer seemed horribly bad.
Why did he do that? Doesn't he see that my shape is alive?. When
such situations occur, there are two possibilities:

1. The bot is playing a weaker human player, and the move is indeed bad.
2. The bot is playing a stronger human, and the move is actually good.

I think it may be a good idea to do something with the weighting in
these situations, so that the relevant moves are added to the tree. In
worst case, a lot of effort is wasted in proving a bad move bad - but
this should not be so serious, as the bad move will likely mean the
opponent has poor chances of winning anyway. In the best case, the
program's blunder is revealed after the fact. This may still leave
little chance of winning, (if the ld error was severe) but at least
the program's counting won't be off for the rest of the game. Since
today's programs don't care for winning margins, counting errors by
even a single point will spell disaster.

I believe this heurtistic would be cheap in terms of computational
cost, but hard to evaluate/tune. Self-play would not be very
effective...
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Re: Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread terry mcintyre
Feed any MC-UCT program the position after White B1, at move 195, and ask the 
probability of a black win. Repeat until the program corrects its estimate.

It would be interesting to determine just how many simulations are needed to 
solve this problem - which is obvious to double-digit kyu players.

Terry McIntyre [EMAIL PROTECTED] 


- Original Message 
From: ivan dubois [EMAIL PROTECTED]
To: computer-go computer-go@computer-go.org
Sent: Wednesday, January 23, 2008 7:17:17 AM
Subject: Re : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies


Hello,

After thinking a bit more about it, I came to the conclusion that the
 so called Bent four in the corner shape, is not such a serious
 scalability killer (I like this term).
Nor is the situation that appears in your game.
Let me explain why : 
It would indeed be a scalability killer if Mogo was 100 % sure that
 some group is dead, when it is actually alive. However what happens is
 that it has some doubts about the situation. It may think for example
 it is 60 % alive and 40 % dead. Of course it would be better for him to
 know the reality, but having some persistent doubt on it is not that
 much detrimental. For example if he has perfect information about the
 rest of the board, he will play perfectly on the rest of the board.  
I propose a chalenge to this list : Find a real scalability issue with
 Mogo or any other actual UCT program. (And prove it)

Ivan   


- Message d'origine 
De : Harald Korneliussen [EMAIL PROTECTED]
À : computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 15h31mn 20s
Objet : [computer-go] Bent four in the corner was:Scalability problem
 of play-out policies

Ivan Dubois mentioned  the bent four in the corner shape as a
scalability killer, a situation where more playouts doesn't help
(much), because playouts systematically misevaluate it. As I
understand it, it could be corrected in the tree, but this is very
unlikely to happen until the very end of a game, by which time it may
be too late (Mogo having worked the entire game for that solid 0.5
win, which turns out to be a solid loss instead because of the
life-and-death misevaluation)

I recalled a KGS game of Mogo I'd looked at, where something very
similar happened, and with a little digging I found it again:

http://files.gokgs.com/games/2007/12/1/Ardalan-MoGoBot3.sgf

It turns out it's not the bent four shape, but I suspect it's
another such shape, where more playouts only confirm that these moves
aren't worth including into the tree, so that UCT catches them very
late, if ever.

If these situations can be reliably created by a human, then indeed
they put an upper limit on the real world scalability of a program.

If I should propose a hackish heuristic to deal with such situations,
this is it: At one point, when the problematic shape appeared, the
human must have done a move that to the computer seemed horribly bad.
Why did he do that? Doesn't he see that my shape is alive?. When
such situations occur, there are two possibilities:

1. The bot is playing a weaker human player, and the move is indeed
 bad.
2. The bot is playing a stronger human, and the move is actually good.

I think it may be a good idea to do something with the weighting in
these situations, so that the relevant moves are added to the tree. In
worst case, a lot of effort is wasted in proving a bad move bad - but
this should not be so serious, as the bad move will likely mean the
opponent has poor chances of winning anyway. In the best case, the
program's blunder is revealed after the fact. This may still leave
little chance of winning, (if the ld error was severe) but at least
the program's counting won't be off for the rest of the game. Since
today's programs don't care for winning margins, counting errors by
even a single point will spell disaster.

I believe this heurtistic would be cheap in terms of computational
cost, but hard to evaluate/tune. Self-play would not be very
effective...
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Re: [computer-go] New scalability study : show uncertainty ?

2008-01-23 Thread terry mcintyre
Filling suc an eye does not require an extremely strong opponent; I am rated 
a mere 9 kyu AGA, and use this method often. 
My opponents also use it every chance they get. When teaching 20 kyu players, 
these known-dead shapes are right at the top of the list. 
 
However, several otherwise strong programs appear to have a blind spot 
regarding these situations. 

- Original Message 
From: Magnus Persson [EMAIL PROTECTED]
To: computer-go@computer-go.org
Sent: Wednesday, January 23, 2008 4:03:26 AM
Subject: Re: [computer-go] New scalability study : show uncertainty ?


Quoting Heikki Levanto [EMAIL PROTECTED]:

 But you still prune moves like filling a one-point eye. We know that
 there is
 a pthological case where that indeed is a correct move. So Valkyria
 will
 never converge to perfect play even with unlimited CPU power.

Yes, this is a known bug. :)

But, I will not fix it until I fixed some more urgent stuff (there is  
a very long list with higher priority). Also I feel that in the case  
of having a really strong program attempting perfect play with this  
bug as the only defect, the opponent has be extremely strong (or  
extremely lucky) to exploit it.
It might even not be possible to exploit aginst perfect play, because  
there may always be simpler ways to kill the group than making en eye  
and then fill it, alternatively let it live small and win on points.

MoGo is a good example of this. I think Valkyria has an edge against  
MoGo in many LD situations, but often MoGo just put territorial  
pressure on the groups leading to positions where the opponent either
  
defends and loses on points or take a gamble, tenuki and die without  
tactical complications.

Magnus

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Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread ivan dubois
Hello,

I agree that the current implementation of Mogo (from what I know about it)  
will not know for sure that the D17 black group is 100% dead.
It will think that it is X%  dead and stick to that estimation, whatever 
thinking time you give it. X is a constant that does not depend of thinking 
time (no scalability).
However, and this can be surprising, I am not sure wether it is really a 
scalability killer for whole board play, because after all, it doesnt have to 
know with 100 % confidence the status of one group to play perfectly.


- Message d'origine 
De : terry mcintyre [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 16h24mn 53s
Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability problem 
of play-out policies


Feed any MC-UCT program the position after White B1, at move 195, and ask the 
probability of a black win. Repeat until the program corrects its estimate.

It would be interesting to determine just how many simulations are needed to 
solve this problem - which is obvious to double-digit kyu players.

Terry McIntyre [EMAIL PROTECTED]
 




- Original Message 
From: ivan dubois [EMAIL PROTECTED]
To: computer-go computer-go@computer-go.org
Sent: Wednesday, January 23, 2008 7:17:17 AM
Subject: Re : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies

Hello,

After thinking a bit more about it, I came to the conclusion that the so called 
Bent four in the corner shape, is not such a serious scalability killer (I 
like this term).
Nor is the situation that appears in your game.
Let me explain why : 
It would indeed be a scalability killer if Mogo was 100 % sure that some 
group is dead, when it is actually alive. However what happens is that it has 
some doubts about the situation. It may think for example it is 60 % alive and 
40 % dead. Of course it would be better for him to know the reality, but having 
some persistent doubt on it is not that much detrimental. For example if he has 
perfect information about the rest of the board, he will play perfectly on the 
rest of the board.  
I propose a chalenge to this list : Find a real scalability issue with Mogo or 
any other actual UCT program. (And prove it)

Ivan  


- Message d'origine 
De : Harald Korneliussen [EMAIL PROTECTED]
À : computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 15h31mn 20s
Objet : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies

Ivan Dubois mentioned  the bent four in the corner shape as a
scalability killer, a situation where more playouts doesn't help
(much), because playouts systematically misevaluate it. As I
understand it, it could be corrected in the tree, but this is very
unlikely to happen until the very end of a game, by which time it may
be too late (Mogo having worked the entire game for that solid 0.5
win, which turns out to be a solid loss instead because of the
life-and-death misevaluation)

I recalled a KGS game of Mogo I'd looked at, where something very
similar happened, and with a little digging I found it again:

http://files.gokgs.com/games/2007/12/1/Ardalan-MoGoBot3.sgf

It turns out it's not the bent four shape, but I suspect it's
another such shape, where more playouts only confirm that these moves
aren't worth including into the tree, so that UCT catches them very
late, if ever.

If these situations can be reliably created by a human, then indeed
they put an upper limit on the real world scalability of a program.

If I should propose a hackish heuristic to deal with such situations,
this is it: At one point, when the problematic shape appeared, the
human must have done a move that to the computer seemed horribly bad.
Why did he do that? Doesn't he see that my shape is alive?. When
such situations occur, there are two possibilities:

1. The bot is playing a weaker human player, and the move is indeed bad.
2. The bot is playing a stronger human, and the move is actually good.

I think it may be a good idea to do something with the weighting in
these situations, so that the relevant moves are added to the tree. In
worst case, a lot of effort is wasted in proving a bad move bad - but
this should not be so serious, as the bad move will likely mean the
opponent has poor chances of winning anyway. In the best case, the
program's blunder is revealed after the fact. This may still leave
little chance of winning, (if the ld error was severe) but at least
the program's counting won't be off for the rest of the game. Since
today's programs don't care for winning margins, counting errors by
even a single point will spell disaster.

I believe this heurtistic would be cheap in terms of computational
cost, but hard to evaluate/tune. Self-play would not be very
effective...
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Re: Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread steve uurtamo
it will only assign it a positive probability of being

dead if there are playouts where the group dies, right?



s.



- Original Message 

From: ivan dubois [EMAIL PROTECTED]

To: computer-go computer-go@computer-go.org

Sent: Wednesday, January 23, 2008 10:51:52 AM

Subject: Re : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies



 Hello,

  

 I agree that the current implementation of Mogo (from what I know about it)  
will not know for sure that the D17 black group is 100% dead.

 It will think that it is X%  dead and stick to that estimation, whatever 
thinking time you give it. X is a constant that does not depend of thinking 
time (no scalability).

 However, and this can be surprising, I am not sure wether it is really a 
scalability killer for whole board play, because after all, it doesnt have to 
know with 100 % confidence the status of one group to play perfectly.

 

 

 - Message d'origine 

De : terry mcintyre [EMAIL PROTECTED]

À : computer-go computer-go@computer-go.org

Envoyé le : Mercredi, 23 Janvier 2008, 16h24mn 53s

Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability problem 
of play-out policies



 Feed any MC-UCT program the position after White B1, at move 195, and ask the 
probability of a black win. Repeat until the program corrects its estimate.



It would be interesting to determine just how many simulations are needed to 
solve this problem - which is obvious to double-digit kyu players.



Terry McIntyre [EMAIL PROTECTED]  

 



 - Original Message 

From: ivan dubois [EMAIL PROTECTED]

To: computer-go computer-go@computer-go.org

Sent: Wednesday, January 23, 2008 7:17:17 AM

Subject: Re : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies



Hello,



After thinking a bit more about it, I came to the conclusion that the so called 
Bent four in the corner shape, is not such a serious scalability killer (I 
like this term).

Nor is the situation that appears in your game.

Let me explain why : 

It would indeed be a scalability killer if Mogo was 100 % sure that some 
group is dead, when it is actually alive. However what happens is that it has 
some doubts about the situation. It may think for example it is 60 % alive and 
40 % dead. Of course it would be better for him to know the reality, but having 
some  persistent doubt on it is not that much detrimental. For example if he 
has perfect information about the rest of the board, he will play perfectly on 
the rest of the board.  

I propose a chalenge to this list : Find a real scalability issue with Mogo or 
any other actual UCT program. (And prove it)



Ivan  





- Message d'origine 

De : Harald Korneliussen [EMAIL PROTECTED]

À : computer-go@computer-go.org

Envoyé le : Mercredi, 23 Janvier 2008, 15h31mn 20s

Objet : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies



Ivan Dubois mentioned  the bent four in the corner shape as a

scalability killer, a situation where more playouts  doesn't help

(much), because playouts systematically misevaluate it. As I

understand it, it could be corrected in the tree, but this is very

unlikely to happen until the very end of a game, by which time it may

be too late (Mogo having worked the entire game for that solid 0.5

win, which turns out to be a solid loss instead because of the

life-and-death misevaluation)



I recalled a KGS game of Mogo I'd looked at, where something very

similar happened, and with a little digging I found it again:



http://files.gokgs.com/games/2007/12/1/Ardalan-MoGoBot3.sgf



It turns out it's not the bent four shape, but I suspect it's

another such shape, where more playouts only confirm that these moves

aren't worth including into the tree, so that UCT catches them very

late, if ever.



If these situations can be  reliably created by a human, then indeed

they put an upper limit on the real world scalability of a program.



If I should propose a hackish heuristic to deal with such situations,

this is it: At one point, when the problematic shape appeared, the

human must have done a move that to the computer seemed horribly bad.

Why did he do that? Doesn't he see that my shape is alive?. When

such situations occur, there are two possibilities:



1. The bot is playing a weaker human player, and the move is indeed bad.

2. The bot is playing a stronger human, and the move is actually good.



I think it may be a good idea to do something with the weighting in

these situations, so that the relevant moves are added to the tree. In

worst case, a lot of effort is wasted in proving a bad move bad - but

this should not be so serious, as the bad move will likely mean the

opponent has poor chances of winning anyway. In the best  case, the

program's blunder is revealed after the fact. This may still leave

little chance of winning, (if the ld error was severe) but at least

the 

Re: [computer-go] Is MC-UCT really scalable against humans?

2008-01-23 Thread Ian Osgood


On Jan 22, 2008, at 2:08 PM, [EMAIL PROTECTED] wrote:

MoGo plays unconventional moves only in the first 10 moves or so.  
That is it plays an unconventional openning. An unconventional  
opening in Go is actaully something that is celebrated for ...


DL


If this is a concern, someone should add a fuseki database to a UCT  
program to see if it improves play. I know that Howard Landman had a  
very complete fuseki DB in his program Poka.


I also wonder how Monte Carlo evaluations would work married to other  
depth-first searches, like Proof-Number.


Ian

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Re : Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread ivan dubois
Hi,

This is correct. 
Do you think there will be no playouts where the group dies ? 
I think there will be around 50% where the group dies. If you think this is not 
the case, please explain to me. 

Ivan

- Message d'origine 
De : steve uurtamo [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 17h22mn 35s
Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability problem 
of play-out policies

it will only assign it a positive probability of being

dead if there are playouts where the group dies, right?



s.



- Original Message 

From: ivan dubois [EMAIL PROTECTED]

To: computer-go computer-go@computer-go.org

Sent: Wednesday, January 23, 2008 10:51:52 AM

Subject: Re : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies



Hello,

  

I agree that the current implementation of Mogo (from what I know about it)  
will not know for sure that the D17 black group is 100% dead.

It will think that it is X%  dead and stick to that estimation, whatever 
thinking time you give it. X is a constant that does not depend of thinking 
time (no scalability).

However, and this can be surprising, I am not sure wether it is really a 
scalability killer for whole board play, because after all, it doesnt have to 
know with 100 % confidence the status of one group to play perfectly.





- Message d'origine 

De : terry mcintyre [EMAIL PROTECTED]

À : computer-go computer-go@computer-go.org

Envoyé le : Mercredi, 23 Janvier 2008, 16h24mn 53s

Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability problem 
of play-out policies



Feed any MC-UCT program the position after White B1, at move 195, and ask the 
probability of a black win. Repeat until the program corrects its estimate.



It would be interesting to determine just how many simulations are needed to 
solve this problem - which is obvious to double-digit kyu players.



Terry McIntyre [EMAIL PROTECTED]  





- Original Message 

From: ivan dubois [EMAIL PROTECTED]

To: computer-go computer-go@computer-go.org

Sent: Wednesday, January 23, 2008 7:17:17 AM

Subject: Re : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies



Hello,



After thinking a bit more about it, I came to the conclusion that the so called 
Bent four in the corner shape, is not such a serious scalability killer (I 
like this term).

Nor is the situation that appears in your game.

Let me explain why : 

It would indeed be a scalability killer if Mogo was 100 % sure that some 
group is dead, when it is actually alive. However what happens is that it has 
some doubts about the situation. It may think for example it is 60 % alive and 
40 % dead. Of course it would be better for him to know the reality, but having 
some  persistent doubt on it is not that much detrimental. For example if he 
has perfect information about the rest of the board, he will play perfectly on 
the rest of the board.  

I propose a chalenge to this list : Find a real scalability issue with Mogo or 
any other actual UCT program. (And prove it)



Ivan  





- Message d'origine 

De : Harald Korneliussen [EMAIL PROTECTED]

À : computer-go@computer-go.org

Envoyé le : Mercredi, 23 Janvier 2008, 15h31mn 20s

Objet : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies



Ivan Dubois mentioned  the bent four in the corner shape as a

scalability killer, a situation where more playouts  doesn't help

(much), because playouts systematically misevaluate it. As I

understand it, it could be corrected in the tree, but this is very

unlikely to happen until the very end of a game, by which time it may

be too late (Mogo having worked the entire game for that solid 0.5

win, which turns out to be a solid loss instead because of the

life-and-death misevaluation)



I recalled a KGS game of Mogo I'd looked at, where something very

similar happened, and with a little digging I found it again:



http://files.gokgs.com/games/2007/12/1/Ardalan-MoGoBot3.sgf



It turns out it's not the bent four shape, but I suspect it's

another such shape, where more playouts only confirm that these moves

aren't worth including into the tree, so that UCT catches them very

late, if ever.



If these situations can be  reliably created by a human, then indeed

they put an upper limit on the real world scalability of a program.



If I should propose a hackish heuristic to deal with such situations,

this is it: At one point, when the problematic shape appeared, the

human must have done a move that to the computer seemed horribly bad.

Why did he do that? Doesn't he see that my shape is alive?. When

such situations occur, there are two possibilities:



1. The bot is playing a weaker human player, and the move is indeed bad.

2. The bot is playing a stronger human, and the move is actually good.



I think it may be a good idea to 

Re: Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread terry mcintyre
I disagree. If the opponent's estimate of the rest of the board is at least as 
good as program XXX, but the opponent knows a particular group is 100% dead, 
where program XXX thinks it might live, the opponent is likely to win, with a 
probability approaching 1.00. Program XXX will be basing its decisions on 
provably false information. The opponent will spend just enough effort to keep 
that group dead, and will otherwise play as well as program XXX on the rest of 
the board.

We have all seen that Mogo is not greedy - it will play suboptimal moves while 
it thinks it has the win. I've read many an argument about how Mogo is actually 
maximizing win probability; this is total fantasy. When obvious yose ( endgame 
) plays or life-making plays are passed up in favor of tossing random stones 
into  perfectly secure eyespace, that is a losing strategy. Better yose 
handling can ( and often does ) make up for earlier mistakes. Random stones in 
one's own area will not help. Under area counting rules, playing the da me ( 
neutral points ) would be better.
 
Terry McIntyre [EMAIL PROTECTED] 
“Wherever is found what is called a paternal government, there is found state 
education. It has been discovered that the best way to insure implicit 
obedience is to commence tyranny in the nursery.”
 
Benjamin Disraeli, Speech in the House of Commons [June 15, 1874]

- Original Message 
From: ivan dubois [EMAIL PROTECTED]
To: computer-go computer-go@computer-go.org
Sent: Wednesday, January 23, 2008 7:51:52 AM
Subject: Re : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies


Hello,

 

I agree that the current implementation of Mogo (from what I know about it)  
will not know for sure that the D17 black group is 100% dead.

It will think that it is X%  dead and stick to that estimation, whatever 
thinking time you give it. X is a constant that does not depend of thinking 
time (no scalability).

However, and this can be surprising, I am not sure wether it is really a 
scalability killer for whole board play, because after all, it doesnt have to 
know with 100 % confidence the status of one group to play perfectly.


 

- Message d'origine 
De : terry mcintyre [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 16h24mn 53s
Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability problem 
of play-out policies


Feed any MC-UCT program the position after White B1, at move 195, and ask the 
probability of a black win. Repeat until the program corrects its estimate.

It would be interesting to determine just how many simulations are needed to 
solve this problem - which is obvious to double-digit kyu players.

Terry McIntyre [EMAIL PROTECTED]
 




- Original Message 
From: ivan dubois [EMAIL PROTECTED]
To: computer-go computer-go@computer-go.org
Sent: Wednesday, January 23, 2008 7:17:17 AM
Subject: Re : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies

Hello,

After thinking a bit more about it, I came to the conclusion that the so called 
Bent four in the corner shape, is not such a serious scalability killer (I 
like this term).
Nor is the situation that appears in your game.
Let me explain why : 
It would indeed be a scalability killer if Mogo was 100 % sure that some 
group is dead, when it is actually alive. However what happens is that it has 
some doubts about the situation. It may think for example it is 60 % alive and 
40 % dead. Of course it would be better for him to know the reality, but having 
some
 persistent doubt on it is not that much detrimental. For example if he has 
perfect information about the rest of the board, he will play perfectly on the 
rest of the board.  
I propose a chalenge to this list : Find a real scalability issue with Mogo or 
any other actual UCT program. (And prove it)

Ivan  


- Message d'origine 
De : Harald Korneliussen [EMAIL PROTECTED]
À : computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 15h31mn 20s
Objet : [computer-go] Bent four in the corner was:Scalability problem of 
play-out policies

Ivan Dubois mentioned  the bent four in the corner shape as a
scalability killer, a situation where more playouts
 doesn't help
(much), because playouts systematically misevaluate it. As I
understand it, it could be corrected in the tree, but this is very
unlikely to happen until the very end of a game, by which time it may
be too late (Mogo having worked the entire game for that solid 0.5
win, which turns out to be a solid loss instead because of the
life-and-death misevaluation)

I recalled a KGS game of Mogo I'd looked at, where something very
similar happened, and with a little digging I found it again:

http://files.gokgs.com/games/2007/12/1/Ardalan-MoGoBot3.sgf

It turns out it's not the bent four shape, but I suspect it's
another such shape, where more playouts only confirm that these moves
aren't worth 

Re: Re : Re : [computer-go] Is MC-UCT really scalable ... is a troll

2008-01-23 Thread Russell Wallace
On Jan 23, 2008 3:44 AM, Don Dailey [EMAIL PROTECTED] wrote:
 This is still nonsense.   UCT in actual real world PRACTICE responds
 dramatically to more hardware,  how can you say it's not clear whether
 it's scalable in practice?

In fairness, he didn't say that. What he said was that our belief
regarding whether or not UCT scales in practice, should be based on
tests on real hardware (which appear to give an answer in the
affirmative), rather than on a mathematical proof of what happens in
the limit as computer time tends to infinity (because what happens in
the limit as time tends to infinity, doesn't necessarily have much
bearing on what happens on real hardware; so tests are more
informative).
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Re: [computer-go] Is MC-UCT really scalable against humans?

2008-01-23 Thread grok
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1


 Sure, 9x9 Go is still a very interesting game. One that can be a
 challenge even for the strongest players in the world. But in my
 opinion it's not nearly as interesting as 19x19 Go. Now if that's a
 point you'd like to argue, fine. But no need to be so patronizing.
 
 The interesting point here is not wether player A likes 9x9 or not.  
 The question is if 19x19 go has properties that are different and  
 relevant for computer go programs. In principle I think there is no  
 difference between 9x9 and 19x19. Humans may deal with the complexity  
 of 19x19 go in a way that is different from what they do on 9x9 go.  
 But then I would say that a human player that play a lot of 9x9 would  
 develop knowledge that only applies to 9x9, but from that I would not  
 conclude that 9x9 is special compared to 19x19. It all boils down to  
 unique positions that has to be analyzed with go knowledge that  
 applies to all sizes of the game.
 
 So feel free to argue that 19x19 has properties that are unique, but  
 in doing so please *specify* exactly what this means and why a  
 computer program has to deal with it to play really strong.
 
 -Magnus

The problem here and elsewhere on the computer-go eList
appears to be the avoidance (for whatever reasons) of coming
to an understanding of a general theory of _emergence_;
and as it applies to gameplay in this case -- especially
regarding Go.

Sure, the rules themselves are the same with both 9x9, 13x13
and 19x19 boardsizes; but it's most likely that _new pattern
relations emerge_ in time and space, with the more complex
development of stone formations, the bigger the board gets.
And that's what's not being properly and explicitly
recognized here: thus all the misunderstanding and flip flop
of positions to take, 'pro or con', as if matters are only
one way with each board size, or with which algorithm or
whatever -- and that's that.

And so then this problem with emergence and dialectics very
much spills over into the problems people here are having
with what to focus on in the programming end of things too.
'Eithor/or' decisions don't often seem to be the best way to
go about approaching problems. And this IMO logical defect
has everything to do with the long reductionist history of
programming and science whcih still plagues universities and
research.

My 2 cents-worth on this.


- -- grok.






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Re : [computer-go] Is MC-UCT really scalable ... is a troll

2008-01-23 Thread ivan dubois
Thanks.

- Message d'origine 
De : Russell Wallace [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 18h07mn 27s
Objet : Re: Re : Re : [computer-go] Is MC-UCT really scalable ... is a troll

On Jan 23, 2008 3:44 AM, Don Dailey [EMAIL PROTECTED] wrote:
 This is still nonsense.  UCT in actual real world PRACTICE responds
 dramatically to more hardware,  how can you say it's not clear whether
 it's scalable in practice?

In fairness, he didn't say that. What he said was that our belief
regarding whether or not UCT scales in practice, should be based on
tests on real hardware (which appear to give an answer in the
affirmative), rather than on a mathematical proof of what happens in
the limit as computer time tends to infinity (because what happens in
the limit as time tends to infinity, doesn't necessarily have much
bearing on what happens on real hardware; so tests are more
informative).
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Re: [computer-go] scalability study - how close to perfection?

2008-01-23 Thread Christoph Birk

On Wed, 23 Jan 2008, Don Dailey wrote:

This bias was clear in 7x7 - I don't expect to see it here but I will
check when there are enough games at the upper levels.


I beg you ... add Mogo_14 to the study, please.

Christoph

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Re: [computer-go] Scalability problem of play-out policies

2008-01-23 Thread Don Dailey


Joel Veness wrote:
 Hi Ivan,

 I like to view game tree search methods as a systematic ways to
 correct static evaluation errors. I don't find it surprising that UCT
 scales well with increasing time and space. I claim that the accuracy
 of the monte-carlo method increases as we get closer to the end of a
 game. UCT helps propagate monte-carlo evaluations from the best
 looking lines deep inside the tree. If the best line of play is deep
 enough and sampled well enough, then positions that might have caused
 problems for the monte-carlo evaluation will eventually be avoided.
 Remember that with UCT, no line of play is avoided forever, no matter
 what the monte-carlo evaluation says. Extra time and space just
 increases the chances of the UCT component correcting any errors in
 the monte-carlo evaluation, which is why I think it scales so well.

 I certainly think it is reasonable to suggest that certain flaws in a
 monte-carlo evaluation function could create scaling issues. This
 could happen if there ever reaches a point that a program is losing
 game after game due to the evaluation function not understanding some
 particular dynamic of the game quick enough to give the UCT search a
 chance of correcting the misconception. However, I actually don't
 think this to be the case in practice.
   
Yes,  you can entertain any unreasonable possibility but it's a waste of
time.   People get some idea in their head that in their mind they can
see as happening,  and perhaps can even construct some corner case that
is possible or plausible, and then it can be endlessly debated but has
nothing to do with anything actually happening.

- Don
 

 I think that why the scaling results are so consistent and smooth is
 due to the imperfection that comes with using a monte-carlo evaluation
 function. We have to deal with stochastic noise, in addition to
 misconceptions due to the method. Since there are so many errors to
 correct (many of them small errors), any extra processing time
 provides ample opportunity to help the program get a better idea of
 the board situation and avoid that game losing blunder. In my opinion,
 this plays a big factor in creating these almost linear scaling
 results that we see regularly.

 Joel


 On Jan 23, 2008 4:16 PM, ivan dubois [EMAIL PROTECTED] wrote:
   
 Sorry, this may very well be nitpicking, but it is not nonsense.
 I just dont like when people are making illegitimate deductions, using the 
 fact that the same word can have two distinct meanings. Anyway all this is 
 just nitpicking from my part, I have to admit.

 What is not nitpicking however, is wether some play-out policy (wich might 
 appear to be working well) can compromise the scalability of UCT at some 
 point. I read that there seemed to be a problem with Fatman's scalability. I 
 dont know what are the latest news about this, but I think you should at 
 least consider the possibility that it may come from some persistent 
 missconception from the play-out policy.
 After all, I may very well be right.
 After thinking a little about it, I came to the conclusion that there can be 
 a scalability problem when :
 There is a bias in the MC evaluation AND there is no move to be made in 
 the UCT part that can partialy correct the missconception of the MC 
 evaluation.
 This happens each time there is a situation that just cannot be settled 
 immediatly, but has to wait the end of the game.
 Now I think I can give you a clean example : The bent four in the corner 
 shape : http://senseis.xmp.net/?BentFourInTheCornerIsDead

 Tell me if I am wrong, but I bet nor your program nor Mogo does scale at all 
 on this situation. That means whatever computing power you can give to it, 
 If i can create such a situation in my game against him, I will probably 
 win. And notice that more computing power will not help Mogo to avoid this 
 situation because it doesnt know it to be a problem.
 Tell me if I am wrong, but I think it is a scalability problem that puts a 
 real limit to the strength it can reach in theory.

 But please, do not miss understand me, I am NOT saying that this is a 
 crucial problem to MC that cannot be fixed. I am sure it CAN be fixed. I am 
 just saying that currently MC programs do not scale infinitely, but I have 
 no doubt that these problems will be corrected as soon as they become 
 crucial to the playing strength.

 Ivan


  Message d'origine 
 De : Don Dailey [EMAIL PROTECTED]
 À : computer-go computer-go@computer-go.org
 Envoyé le : Mercredi, 23 Janvier 2008, 4h44mn 17s
 Objet : Re: Re : Re : [computer-go] Is MC-UCT really scalable ... is a troll



 ivan dubois wrote:
 
 Thanks !
 I think I agree with everything you said.
 After some reasoning, I changed my opinion about the practical scalability 
 of Mogo. It does have some missconceptions about eyes, but as you said, it 
 can be corrected by the UCT part. I tried to find a situation where the UCT 
 part does not help until the situation 

Re: [computer-go] scalability study - how close to perfection?

2008-01-23 Thread Don Dailey
Just cool it. We intend to add 3 more mogo levels soon.   

- Don


Christoph Birk wrote:
 On Wed, 23 Jan 2008, Don Dailey wrote:
 This bias was clear in 7x7 - I don't expect to see it here but I will
 check when there are enough games at the upper levels.

 I beg you ... add Mogo_14 to the study, please.

 Christoph

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Re: [computer-go] scalability study - how close to perfection?

2008-01-23 Thread terry mcintyre
May I suggest a fundamental limit to the utility of this scalability study?

We are comparing three programs to each other, IIRC - Fatman, Mogo, and Gnugo.

All three are known to have certain odd little quirks. The two MC programs, in 
particular, are
known to be deficient when addressing certain LD situations. They may continue 
to get 
better with respect to each other for some time yet. They will reach a sort of 
local optimum
with respect to each other.

At the end of the day, a halfway clever 9 kyu player will play the vital point 
on a bulky five,
or induce the programs to create a square four, or some other common strategem, 
and the
standard of play may be shown to have some serious gaps. The programs will be 
perfect
or near genius level only against other programs. This is a variation of the 
problems faced by Sluggo --
if I recall correctly, it could give Gnugo a 6 or 7 stone handicap, which was a 
very impressive achievement - but it fell flat against the average human player.

I think this study is useful - that's why I'm lending four cores - but I also 
think we should create 
some test cases and see whether more playouts will cause the programs to 
resolve these test cases 
properly, or not. When a group is provably dead, then it's contribution to the 
final estimation should be that of a 100% dead group, not 50% or 80%. I know 
this is difficult in the general case ( there's a paper demonstrating that it 
is NP-hard, if I recall correctly ), but let's try to test the 20-kyu and 
10-kyu cases,
at least.

Otherwise, I suspect that it may be a very long time before these fairly common 
corner cases are handled correctly. 

Terry McIntyre [EMAIL PROTECTED] 




  

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Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread ivan dubois
By the way, my argument still applies when there are no outside liberties, 
because the eye filing itself is a long enough UCT trap (a sequence of moves 
that appears to be just like null moves).  
I gave a theoretical argument, but actualy it is not very surprising. Did you 
ever wonder why Mogo, being now so strong, could still exhibit so basic and 
stupid blind spots ? The explanation is very simple : Those blind spots reveal 
the fact that some aspects of its understanding do not scale as fast as the 
other aspects. Actualy for some aspects, it does not scale at all, from a 
practical point of view.

Ivan   


- Message d'origine 
De : Michael Williams [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 20h38mn 32s
Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability problem 
of play-out policies

ivan dubois wrote:
 I agree that the current implementation of Mogo (from what I know about 
 it)  will not know for sure that the D17 black group is 100% dead.
 It will think that it is X%  dead and stick to that estimation, whatever 
 thinking time you give it. X is a constant that does not depend of 
 thinking time (no scalability).

How are you arriving at this conclusion?  It makes no sense to me.
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Re: Re : Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread Michael Williams

ivan dubois wrote:
Hello, 


- Message d'origine 
De : Michael Williams [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 20h38mn 32s
Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability problem 
of play-out policies

ivan dubois wrote:
I agree that the current implementation of Mogo (from what I know about 
it)  will not know for sure that the D17 black group is 100% dead.
It will think that it is X%  dead and stick to that estimation, whatever 
thinking time you give it. X is a constant that does not depend of 
thinking time (no scalability).



How are you arriving at this conclusion?  It makes no sense to me.



Actually this is not true for this exact situation, but I think it is true if 
the black group has enough external liberties.
Suppose it has 10 outside liberties, to make things very clear. 
For the simplicity of my argument, suppose also that the big eye is almost entirely filled with white stones (minus 1 liberty) 
Here is my reasoning : 
Starting from the root, there are some playouts where the black group dies, and other where it lives. Let us note X the proportion of playouts that end with the black group having been captured.

Now is there any move A, starting from the root, that will change this 
ratio if you start the random playouts just after A ? I think clearly, the 
answer is no, do you agree with that ? The only relevant possible move would be 
to fill a liberty, but since all liberties will be filled anyway during the 
playouts, this will not change anything to the scenario. The only thing that 
matters is wether or not white plays first at the vital point every time the 
eye is reduced during the playouts.
 Using the same argument, there exists no sequence of less than 8 moves that can change the value of X. 
This means all these sequences of liberty filling will be considered to have exactly the same value than playing a null move. 
I think it implies that uct will never (of course in theory it will at some point but I say it would require absurd computing time) find the sequence that captures the group with 100% confidence, because this sequence begins with 8 apparently useless moves.


You speak to imprecisely for me, sorry.  When questioned, you reverse position.

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Re: Re : Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread steve uurtamo
i.e.,

any case where discovering a particular position
would require making illegal moves during that
playout with respect to the move policy in place.

so for instance, if the only way to discover the death of a
group is to play inside one-point eyes, and there's a playout
policy that says to never play inside one-point eyes, then
the death of the relevant group will never be discovered, and
will have zero estimated probability of ever occurring.  not that
it will have vanishingly small probability, but that it will have
p=0.

if this group is all that keeps two larger groups connected, for instance,
then this is a problem for the understanding of the whole board
situation.

this has been beaten badly to death, however, so i'll take any
responses off-list.

s.

- Original Message 
From: ivan dubois [EMAIL PROTECTED]
To: computer-go computer-go@computer-go.org
Sent: Wednesday, January 23, 2008 11:45:01 AM
Subject: Re : Re : [computer-go] Bent four in the corner was:Scalability 
problem of play-out policies


Hi,

This is correct. 
Do you think there will be no playouts where the group dies ? 
I think there will be around 50% where the group dies. If you think
 this is not the case, please explain to me. 

Ivan

- Message d'origine 
De : steve uurtamo [EMAIL PROTECTED]
À : computer-go computer-go@computer-go.org
Envoyé le : Mercredi, 23 Janvier 2008, 17h22mn 35s
Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability
 problem of play-out policies

it will only assign it a positive probability of being

dead if there are playouts where the group dies, right?



s.



- Original Message 

From: ivan dubois [EMAIL PROTECTED]

To: computer-go computer-go@computer-go.org

Sent: Wednesday, January 23, 2008 10:51:52 AM

Subject: Re : [computer-go] Bent four in the corner was:Scalability
 problem of play-out policies



Hello,

  

I agree that the current implementation of Mogo (from what I know about
 it)  will not know for sure that the D17 black group is 100% dead.

It will think that it is X%  dead and stick to that estimation,
 whatever thinking time you give it. X is a constant that does not depend of
 thinking time (no scalability).

However, and this can be surprising, I am not sure wether it is really
 a scalability killer for whole board play, because after all, it doesnt
 have to know with 100 % confidence the status of one group to play
 perfectly.





- Message d'origine 

De : terry mcintyre [EMAIL PROTECTED]

À : computer-go computer-go@computer-go.org

Envoyé le : Mercredi, 23 Janvier 2008, 16h24mn 53s

Objet : Re: Re : [computer-go] Bent four in the corner was:Scalability
 problem of play-out policies



Feed any MC-UCT program the position after White B1, at move 195, and
 ask the probability of a black win. Repeat until the program corrects
 its estimate.



It would be interesting to determine just how many simulations are
 needed to solve this problem - which is obvious to double-digit kyu
 players.



Terry McIntyre [EMAIL PROTECTED]  





- Original Message 

From: ivan dubois [EMAIL PROTECTED]

To: computer-go computer-go@computer-go.org

Sent: Wednesday, January 23, 2008 7:17:17 AM

Subject: Re : [computer-go] Bent four in the corner was:Scalability
 problem of play-out policies



Hello,



After thinking a bit more about it, I came to the conclusion that the
 so called Bent four in the corner shape, is not such a serious
 scalability killer (I like this term).

Nor is the situation that appears in your game.

Let me explain why : 

It would indeed be a scalability killer if Mogo was 100 % sure that
 some group is dead, when it is actually alive. However what happens is
 that it has some doubts about the situation. It may think for example
 it is 60 % alive and 40 % dead. Of course it would be better for him to
 know the reality, but having some  persistent doubt on it is not that
 much detrimental. For example if he has perfect information about the
 rest of the board, he will play perfectly on the rest of the board.  

I propose a chalenge to this list : Find a real scalability issue with
 Mogo or any other actual UCT program. (And prove it)



Ivan  





- Message d'origine 

De : Harald Korneliussen [EMAIL PROTECTED]

À : computer-go@computer-go.org

Envoyé le : Mercredi, 23 Janvier 2008, 15h31mn 20s

Objet : [computer-go] Bent four in the corner was:Scalability problem
 of play-out policies



Ivan Dubois mentioned  the bent four in the corner shape as a

scalability killer, a situation where more playouts  doesn't help

(much), because playouts systematically misevaluate it. As I

understand it, it could be corrected in the tree, but this is very

unlikely to happen until the very end of a game, by which time it may

be too late (Mogo having worked the entire game for that solid 0.5

win, which turns out to be a solid loss instead because of the

life-and-death misevaluation)



I recalled a KGS game of Mogo I'd 

Re : [computer-go] Bent four in the corner was:Scalability problem of play-out policies

2008-01-23 Thread ivan dubois
I gave you a proof of what I am claiming, I really dont see what I can do more.
Anyway we all now all this is just a waste of time for pleasure. People who are 
really working on a UCT engine (I dont anymore) will find solutions to these 
problems as soon as they become relevant to playing strength.

 You speak to imprecisely for me, sorry.  When questioned, you reverse 
 position.

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[computer-go] CGOS 9x9 is down

2008-01-23 Thread Jason House
Maybe it's just a temporary thing, but I just happened to check and CGOS was
down...  I get lots of messages like the following:

22:43:00Server startup return code: 1   msg: couldn't open socket:
connection refused
22:43:00Cannot connect to server.  Will retry shortly
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Re: [computer-go] Sylvain Gelly thesis in english

2008-01-23 Thread Christoph Birk

On Sun, 13 Jan 2008, Sylvain Gelly wrote:

Google finds it:
http://tao.lri.fr/Papers/thesesTAO/SylvainGellyThesis.pdf



That is NOT the latest version. Please at least let me put the latest
version on my web site, it took me so long to correct it :).


Where may we find the latest version?

Christoph

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[computer-go] Re: [Cgos-developers] CGOS 9x9 is down

2008-01-23 Thread Don Dailey
I am in the process of restarting it and you just happened to be there.

There is still a bug in the server where occasionally the server will
not realize a bot disconnected.   In those cases it thinks they are
still logged on and won't let them log back on.

So until I find the bug,  the server needs to be restarted
occasionally.We should put this in bugzilla or whatever sourceforge
uses to track bugs. I should be able to look into this next week, 
but I'm booked solid this week.

- Don



Jason House wrote:
 Maybe it's just a temporary thing, but I just happened to check and CGOS was
 down...  I get lots of messages like the following:

 22:43:00Server startup return code: 1   msg: couldn't open socket:
 connection refused
 22:43:00Cannot connect to server.  Will retry shortly

   
 

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Re: [computer-go] 19x19 MC improvement

2008-01-23 Thread Eric Boesch
On Jan 23, 2008 3:11 AM, Hiroshi Yamashita [EMAIL PROTECTED] wrote:
 2. Change UCT exploration parameter
   exp_param = sqrt(2.0);
   uct = exp_param * sqrt( log(sum of all children playout) /
 (number of child playout) );
   uct_value = (child winning rate) + uct;

  I changed exp_param sqrt(2.0) to sqrt(0.1).

2.0 to 0.1? That's a pretty big step. I did notice that libego worked
better with lower constants than recommended by the formula -- in
libego, the original UCB1 formula corresponds to an explore_rate
coefficient of 8, but the default explore_rate coefficient of 1 seemed
to be about the best.

I am curious if any of those of you who have heavy-playout programs
would find a benefit from the following modification:

   exp_param = sqrt(0.2); // sqrt(2) times the original parameter value.
   uct = exp_param * sqrt( log(sum of all children playout)
   * (child-win-rate-2) /
 (number of child playout) );
   uct_value = (child winning rate) + uct;

where child-win-rate-2 is defined as

(#wins + 1) / (#wins + #losses + 2)

If it happens that you do the equivalent of initializing #wins to 1
and #losses to 1 (in libego, setting the initial bias to 2), then you
can just use your original (child winning rate) value. (W+1)/(W+L+2)
is the mean of a beta(W+1,L+1) random variable, which is what you get
when you start with a uniform(0,1) distribution and condition it by
the observation of a W-L record. The explore parameter inside the
square root is doubled so that when you have an average
child-win-rate-2 value of 0.5, the formula returns the same value as
before. (Using an initial bias of 2.0 seems like a good thing anyhow.)

Adding this extra term seemed to help a bit (57% +/- 4.5% win rate over
unmodified program) when the basic playouts were uniform.

This change tends to make the formula stick with proven winners more
than before, so you might need to increase the explore rate by a
little more than sqrt(2).

Your mileage may vary -- I'd also like to know if you try this change
and find it unhelpful.

The justification is that the standard deviation of a beta(1,21) is
lower than the standard deviation of a beta(11,11) variable. The error
term of a beta(21,1) is lower too, but applying the (L+1)/(W+L+2) term
to the UCB1 formula can yield nonsensical results where when two moves
have the same bias, the one with the worse win-loss record is assigned
the higher UCB1 value.
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Re: [computer-go] 19x19 MC improvement

2008-01-23 Thread Jason House

On Wed, 2008-01-23 at 18:57 -0500, Eric Boesch wrote:
 I am curious if any of those of you who have heavy-playout programs
 would find a benefit from the following modification:
 
exp_param = sqrt(0.2); // sqrt(2) times the original parameter value.
uct = exp_param * sqrt( log(sum of all children playout)
* (child-win-rate-2) /
  (number of child playout) );
uct_value = (child winning rate) + uct;
 
 where child-win-rate-2 is defined as
 
 (#wins + 1) / (#wins + #losses + 2)


I'm surprised to see that this works as listed, because the math looks
all wrong to me...

I usually think of UCT as being based on the sample variance.
It looks like you're using:
  sqrt(child_win_rate_2/number_child_playouts)
Standard bernouli trials yield: 
  sqrt(child_win_rate*(1-child_win_rate)/number_child_playouts)
Beta distribution yields:
  sqrt(win_rate_2*(1-win_rate_2)/(number_child_playouts+3))

When using the full beta distribution theory, uct_value would be:
  child_win_rate_2 + uct

Is it possible you have a typo in your uct calculation?  If not, you're
really favoring high win rates over low win rates.  Or maybe with
inversions of wins and losses between ply, you're favoring exploration
of the less probable moves?  I'd really be interested in hearing more
about what you did!

PS: I'm glad to see someone else using the beta distribution theory.  I
posted it to the mailing list long ago, but didn't think anyone found it
very interesting/useful.

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Re: [computer-go] Sylvain Gelly thesis in english

2008-01-23 Thread elife2008
http://www.lri.fr/~gelly/Publications.htm

On 1/24/08, Christoph Birk [EMAIL PROTECTED] wrote:
 On Sun, 13 Jan 2008, Sylvain Gelly wrote:
  Google finds it:
  http://tao.lri.fr/Papers/thesesTAO/SylvainGellyThesis.pdf
 
  That is NOT the latest version. Please at least let me put the latest
  version on my web site, it took me so long to correct it :).

 Where may we find the latest version?

 Christoph

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Re: [computer-go] scalability study - how close to perfection?

2008-01-23 Thread Darren Cook
 ... it would explain the scaling curve flattening out.
 
 Though the curve can also be flattened/made-curvier by changing the base
 of the x-axis. Currently it is log-2. Proportional to actual playouts
 would make it appear flatter.
   
 No, that would make it appear more curved if I understand your
 terminology correctly.   IN other words, it would be less of a straight
 line if it was not log(2) and instead was just number of play-outs.

Hi Don,
We're saying the same thing. By becoming flatter I mean the line on
the chart is becoming closer to being parallel with the x-axis. (I.e.
flat line means you've hit perfect play.)

Darren

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Re: [computer-go] Re: [Cgos-developers] CGOS 9x9 is down

2008-01-23 Thread Michael Williams

Just allow any login to superceed any previous login.


Don Dailey wrote:

I am in the process of restarting it and you just happened to be there.

There is still a bug in the server where occasionally the server will
not realize a bot disconnected.   In those cases it thinks they are
still logged on and won't let them log back on.

So until I find the bug,  the server needs to be restarted
occasionally.We should put this in bugzilla or whatever sourceforge
uses to track bugs. I should be able to look into this next week, 
but I'm booked solid this week.


- Don



Jason House wrote:

Maybe it's just a temporary thing, but I just happened to check and CGOS was
down...  I get lots of messages like the following:

22:43:00Server startup return code: 1   msg: couldn't open socket:
connection refused
22:43:00Cannot connect to server.  Will retry shortly

  



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