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clyring
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Re: Replace the Scoring Function
« Reply #15 on: Apr 22nd, 2013, 3:55pm »
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on Apr 22nd, 2013, 2:13pm, browni3141 wrote:
Well, technically the first is not a draw, but what does you think it should be? What does your intuition tell you? From my perspective that position "is" a draw, even if it isn't Smiley

My intuition tells me that the player who made the move to create such a position in the first place (here, Silver) has a forced loss that is very easy. Gold can just shuffle his elephant one step north then one step south every move and win by immobilization because he will not repeat any position without Silver repeating a position at least as many times. (But my intuition only told me this because I took it on as a problem with you in the chatroom in the past. Smiley)
 
(That said, I would have no problems as a player calling these positions drawn, either, but calling these positions drawn with the current repetition rule seems somewhat silly to me given that it naturally produces an easily predictable winner with no need to actually play out the ridiculous number of moves involved. That said, if Gold doesn't know the winning technique, I of course have no problem calling it drawn. Cheesy)
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mattj256
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Re: Replace the Scoring Function
« Reply #16 on: Apr 22nd, 2013, 10:58pm »
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on Apr 22nd, 2013, 10:05am, Nombril wrote:
And note that all three of mattj256's examples are not draws.  As Hippo pointed out, the "typical" draw of rabbits in the middle was proven by Hippo to not actually be a draw, but there will be a winner based on the repetition rule leading to "immobilization".  And for the other two examples, it is easy to open the position without sacrificing material.

I was wrong about the last two cases and I probably should have acknowledged that earlier.  The first case, while theoretically a win for one player, would take a couple gazillion years to play under best play.
 
on Apr 22nd, 2013, 10:05am, Nombril wrote:
Oh, a potential concern for adjudication:  In a bot vs human game, does this give an unfair advantage to the human player?

It seems to me that the only time the scoring function comes up in practice is when the human is much better than the bot and chooses to prolong the game rather than end it.  Or when two humans are totally fooling around and neither has any intention of winning.  I personally don't care if a regular (non-event) gameroom game is decided by score, even if that score leads to the "wrong" player winning.
 
This is my attempt to eliminate the scoring function from event games.
 
Proposed rules
(1) If a tournament game lasts longer than X amount of time, the game is adjourned and recontinued at a later time as determined by the Tournament Director and both players.  If a non-event game takes longer than X amount of time it is decided by a scoring function that might or might not be accurate.
(2) If a player goes 50 consecutive turns without moving a rabbit forward, pushing or pulling an opponent's rabbit forward, capturing an opponent's piece or having his/her own piece captured, that player loses.  Sacrificed pieces are treated exactly the same as any other capture.  
(3) If one player has all eight rabbits on the same rank, the other player may not end his/her turn with all eight rabbits on the rank immediately in front unless doing so leads to an immediate win by immobilization.
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Re: Replace the Scoring Function
« Reply #17 on: Apr 23rd, 2013, 2:04am »
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My intuition tells me that the player who made the move to create such a position in the first place (here, Silver) has a forced loss that is very easy. Gold can just shuffle his elephant one step north then one step south every move and win by immobilization because he will not repeat any position without Silver repeating a position at least as many times.

 
I don't think so. Suppose the position is stalemated at the beginning.
1g Ra1 Rb1 Rc1 Cd1 Re1 Rf1 Rg1 Rh1 Ha2 Hb2 Cc2 Ed2 De2 Df2 Mg2 Rh2
1s ha7 mb7 cc7 cd7 ee7 hf7 dg7 dh7 ra8 rb8 rc8 rd8 re8 rf8 rg8 rh8
2g Ed2n
2s ee7s
3g Ed3s
3s ee6s
4g Ed2n
4s ee5n ee6n
5g Ed3s
5s ha7s
6g Ed2n
6s ha6n
7g - if gold moves Elephant back, this repeats the position, so gold has to play another move.
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Re: Replace the Scoring Function
« Reply #18 on: Apr 23rd, 2013, 6:54am »
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on Apr 23rd, 2013, 2:04am, Boo wrote:

 
I don't think so. Suppose the position is stalemated at the beginning.
1g Ra1 Rb1 Rc1 Cd1 Re1 Rf1 Rg1 Rh1 Ha2 Hb2 Cc2 Ed2 De2 Df2 Mg2 Rh2
1s ha7 mb7 cc7 cd7 ee7 hf7 dg7 dh7 ra8 rb8 rc8 rd8 re8 rf8 rg8 rh8
2g Ed2n
2s ee7s
3g Ed3s
3s ee6s
4g Ed2n
4s ee5n ee6n
5g Ed3s
5s ha7s
6g Ed2n
6s ha6n
7g - if gold moves Elephant back, this repeats the position, so gold has to play another move.

This produces the initial position with Silver to move only for the second time (Side to move is important in these repetition fights--That the position has appeared once with Gold to move does not limit Gold and can only hinder Silver.), and to put Gold in this situation he has needed to create the same position after 4s and 6s.
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Re: Replace the Scoring Function
« Reply #19 on: Apr 23rd, 2013, 8:55am »
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>Use a human adjudicator (or panel of adjudicators)!
 
Thanks for the suggestion Mathew. Please consider these points and see if it might change your mind.
 
1. It adds a burden of having to pick human adjudicators for every important game just in case the game ends on time. Most of the time it won't be needed; so we will get lazy and not always do it and get away with it. Except one day when we are least expecting it a game will end on time and we will have forgotten to pick the human adjudicators before hand and find ourselves in a mess.
 
The reason I got rid of draws (even though they were so rare) was because it adds a burden to planning a tournament. In case a draw happens you have to have all the rules in place to deal with it. The tournament coordinators and players have to be ready to deal with it. As a tournament coordinator you find yourself hoping that a draw does not happen.
 
"However, in practice I was finding that for elimination type tournaments (like the finals of our world championship tournament) I did not want there to be any possibility of draws, because another game has to be played to break the draw and that makes the tournament schedule less predictable."
 
Getting rid of things that add a burden to running a tournament can only be appreciated after you've run some tournaments Smiley
 
Also this proposal breaks a couple of fundamental truths you expect from perfect information games:
 
2. The result of the game must be consistently reproducible.
 
3. The result of the game must be completely in control of the players.
 
If a different set of human adjudicators were selected the result of the game could turn out different; violating #2. Now we could have the rules specify that particular bots running in a controlled environment would make the decision so that it is always consistent (also this would eliminate the burden of having to pick adjudicators), but it would still violate #3. One could argue that if the evaluation function was deterministic and made public it does not violate #3 because that's also what a simple scoring function is. That's theoretically true, but practically if as a dumb human I can't figure out in real time during the game how it would be evaluated then I am lacking the information I need to make the move decisions during the game. So the game essentially feels like it's not in my control. This is why the current scoring function is dead simple and doesn't even use any formulas.
 
I hope my explanation will convince you. I appreciate you bringing this up though. It's always good to question why things are the way they are.
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Re: Replace the Scoring Function
« Reply #20 on: Apr 23rd, 2013, 11:00am »
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This produces the initial position with Silver to move only for the second time (Side to move is important in these repetition fights--That the position has appeared once with Gold to move does not limit Gold and can only hinder Silver.), and to put Gold in this situation he has needed to create the same position after 4s and 6s.

 
I meant that if it can be produced for the second time, it can also be produced for the 3rd time. You need to repeat the same sequence 5g-6s once more:
5g Ed3s
5s ha7s
6g Ed2n
6s ha6n
7g Ed3s 7s ha7s 8g Ed2n 8s ha6n
9g - gold cant move Ed3s.
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Re: Replace the Scoring Function
« Reply #21 on: Apr 23rd, 2013, 3:30pm »
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on Apr 23rd, 2013, 11:00am, Boo wrote:

 
I meant that if it can be produced for the second time, it can also be produced for the 3rd time.

 
1g Ra1 Rb1 Rc1 Cd1 Re1 Rf1 Rg1 Rh1 Ha2 Hb2 Cc2 Ed2 De2 Df2 Mg2 Rh2  
1s ha7 mb7 cc7 cd7 ee7 hf7 dg7 dh7 ra8 rb8 rc8 rd8 re8 rf8 rg8 rh8  
2g Ed2n  
2s ee7s  
3g Ed3s  
3s ee6s  
4g Ed2n  
4s ee5n ee6n  
5g Ed3s
5s ha7s
6g Ed2n
6s ha6n
7g Ed3s
7s ha7s
8g Ed2n
8s ha6n
Quote:
9g - gold cant move Ed3s.

Isn't move 8s illegal, creating the same position that move 4s and move 6s also created?
« Last Edit: Apr 23rd, 2013, 4:02pm by Fritzlein » IP Logged

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Re: Replace the Scoring Function
« Reply #22 on: Apr 23rd, 2013, 3:33pm »
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on Apr 22nd, 2013, 10:58pm, mattj256 wrote:
(1) If a tournament game lasts longer than X amount of time, the game is adjourned and recontinued at a later time as determined by the Tournament Director and both players.

This could delay an elimination tournament an entire week if the players live in different time zones and have incompatible schedules.
« Last Edit: Apr 23rd, 2013, 4:03pm by Fritzlein » IP Logged

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Re: Replace the Scoring Function
« Reply #23 on: Apr 23rd, 2013, 3:56pm »
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on Apr 22nd, 2013, 2:13pm, browni3141 wrote:
Well, technically the first is not a draw, but what does you think it should be? What does your intuition tell you? From my perspective that position "is" a draw, even if it isn't Smiley

So if you were the human adjudicator, you would rule this position a draw?  What if it were an elimination tournament in which a draw would mean all other players have to wait a week for the drawn game to be replayed?
 
There is a tremendous convenience to having no draws; if you want to allow draws you have to make a pretty strong case for it, in addition to your case for using a human adjudicator rather than using a scoring function.  In my opinion, Arimaa should not allow for draws until we exhaust all reasonable options for determining a winner by other means.
 
In Chinese chess (xiangqi) they use a human arbiter to prevent draws that would otherwise occur over the board.  That is to say, if the two players are just shuffling pieces, an arbiter is permitted to tell one of the players that it is his fault the game is not making progress.  The player deemed at fault has to make a different move or lose.
 
In a sense, the current repetition rule is like that.  If one player locks up a position, the other player can do the "Hippo shuffle" until the first player is forced to repeat.  Thus whoever puts the last brick in the wall loses.  Translation: You lose because it is your fault the game stalemated.  You had no plan to make progress.  You decided to merely block the other guy's progress instead of trying to make headway yourself.  Exactly as you aren't allowed to create an infinite loop by undoing the other guy's move, you aren't allowed to perfect a stalemate position.
 
But this might not seem like an intuitive rule once we see how draws actually emerge in practice.  Maybe the way drawn positions emerge would make the current rule reward turtling rather than punishing it.
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Re: Replace the Scoring Function
« Reply #24 on: Apr 23rd, 2013, 4:00pm »
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on Apr 19th, 2013, 1:48pm, browni3141 wrote:
http://arimaa.com/arimaa/gameroom/comments.cgi?gid=246143

By the way, this game has a simple fix other than changing the scoring function: change the time control from 1d/60d/100/0/300d/21d to 1d/60d/100/0/360d/21d.
 
I would rather have Postal Mixer games spilling over into the next calendar year than have them cut off prematurely.  Why not allow a full year?  They will still be over before the next Postal Mixer starts.  The game in question would have ended naturally by move 120.
« Last Edit: Apr 23rd, 2013, 4:05pm by Fritzlein » IP Logged

mattj256
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Re: Replace the Scoring Function
« Reply #25 on: Apr 24th, 2013, 1:23am »
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on Apr 23rd, 2013, 8:55am, omar wrote:
>Use a human adjudicator (or panel of adjudicators)!
 
Thanks for the suggestion Mathew. Please consider these points and see if it might change your mind.
It was actually browni3141's suggestion which I was agreeing with.  
Thanks for indulging me Omar and Fritzlein.  
 
I think I'm finally convinced to abandon the proposal to change the scoring function:
1. Running a tournament is already a lot of work, and if I'm going to push for a procedure that will make more work for the tournament director there has to be a stronger rationale than that it MIGHT be useful.
2. Arimaa is currently a perfect information game and it should stay that way.
3. The people that are actually running the tournaments don't want to allow draws, or allow long tournament games to be postponed, or move to "sudden death" time controls, and none of those are things I feel strongly about.  If I were dead-set on removing the scoring function I would be pushing for one of those three.  Which I'm not.
 
on Apr 22nd, 2013, 10:58pm, mattj256 wrote:
Proposed rules
(1) If a tournament game lasts longer than X amount of time, the game is adjourned and recontinued at a later time as determined by the Tournament Director and both players.  If a non-event game takes longer than X amount of time it is decided by a scoring function that might or might not be accurate.
(2) If a player goes 50 consecutive turns without moving a rabbit forward, pushing or pulling an opponent's rabbit forward, capturing an opponent's piece or having his/her own piece captured, that player loses.  Sacrificed pieces are treated exactly the same as any other capture.  
(3) If one player has all eight rabbits on the same rank, the other player may not end his/her turn with all eight rabbits on the rank immediately in front unless doing so leads to an immediate win by immobilization.

I'm abandoning #1.  Proposed rule #2 is the "you lose if you don't make progress in 50 moves" rule.  And proposed rule #3 prevents the pathological setup which I still dislike.  
 
If you ignore #3 and produce that setup, then rule #2 says that the FIRST player to make the row of eight has to sacrifice his pieces one by one and then lose by immobilization.  Maybe #2 should be tweaked, or maybe that's an acceptable outcome?  Sorry if I'm being pedantic but I really don't like the way the rules handle that particular board setup.
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Re: Replace the Scoring Function
« Reply #26 on: Apr 24th, 2013, 1:36pm »
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Your rule #2 doesn't obviate the need for a repetition rule.  Imagine a stalemate position in which each side has a hostaged rabbit behind enemy lines.  Every 48 moves or so each player could dislodge the enemy rabbit forward to reset the clock, then dislodge it back the next move.  Thus you haven't found a way to determine a winner, in a guaranteed reasonable number of moves, for all positions in which neither player is making progress.
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Re: Replace the Scoring Function
« Reply #27 on: Apr 24th, 2013, 3:33pm »
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on Apr 23rd, 2013, 8:55am, omar wrote:
>Use a human adjudicator (or panel of adjudicators)!
 
Thanks for the suggestion Mathew. Please consider these points and see if it might change your mind.
on Apr 24th, 2013, 1:23am, mattj256 wrote:

It was actually browni3141's suggestion which I was agreeing with.  
Thanks for indulging me Omar and Fritzlein.  

Yes, but browni3141 is Mathew. You are but one of three members named Mat(t)hew who have participated in this thread. I thought your name was spelled more like mine with two T's, anyway! Tongue
« Last Edit: Apr 24th, 2013, 3:53pm by clyring » IP Logged

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Re: Replace the Scoring Function
« Reply #28 on: Apr 24th, 2013, 9:14pm »
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on Apr 24th, 2013, 3:33pm, clyring wrote:
Yes, but browni3141 is Mathew.
[removes foot from mouth.]  Where are people's names listed?  (Sorry browni3141...)
 
on Apr 24th, 2013, 1:36pm, Fritzlein wrote:
Your rule #2 doesn't obviate the need for a repetition rule.
Sorry I wasn't clear.  I meant in addition to the repetition rule.  The repetition rule by itself will ensure that any position is a theoretical win for one player, but reaching that win in practice could still take a billion moves.
 
You're right that my rule #2 as written doesn't address the case where both players do the hokey-pokey with an enemy rabbit.
 
Do you agree with the sentiment behind rule #2?  These billion-move situations are maybe not relevant for tournament play but they still bother me...
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Re: Replace the Scoring Function
« Reply #29 on: Apr 25th, 2013, 8:26am »
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on Apr 24th, 2013, 9:14pm, mattj256 wrote:
Do you agree with the sentiment behind rule #2?  These billion-move situations are maybe not relevant for tournament play but they still bother me...

If it turns out there are positions where both players are unable (or unwilling) to force goal, and the repetition rule takes an unreasonably long time to determine a winner, and there is a simple rule that determines a winner in a reasonable amount of time, but that simple rule doesn't accidentally change the result of games that were working their way toward a natural conclusion, then yes, I'm all for it.
 
I'm afraid, however, that if you construct a rule to address a specific position that will never, ever happen (sixteen rabbits deadlocked on ranks four and five), then there is a low probability that it will help in situations that actually arise.  Most likely a fifty-move rule in Arimaa would never be invoked, so it would be extra complexity for no gain.  If it were ever invoked, there's a fair chance it would be in a situation unlike the ones we have anticipated so far, and we would realize then it isn't the best fix for the problem at hand.
 
In a nutshell, those are my two reasons for not solving the problem now.
1) Extra complexity is an immediate, tangible evil; the good we are trying to attain is distant and uncertain.
2) We can have no confidence we are addressing the problem correctly when we have almost no data as to what the problem is.
 
I applied the same logic to persuade Omar not to change the setup rules.  He wanted to put to rest any possible speculation that Gold has an advantage over Silver or vice versa.  His proposal for setup was
i) Gold places one piece and one rabbit
ii) Silver places two pieces and two rabbits
iii) Gold places two pieces and two rabbits
iv) Silver places two pieces and two rabbits
...
ix) Gold places his final piece and final rabbit and takes two steps.
x) Silver takes four steps, and the game proceeds normally from there.
 
My argument was that, admittedly, the current rules might favor Gold or might favor Silver.  But imbalance hasn't been a problem yet.  If one side has the advantage, we can't tell which it is.  So (1) don't add the immediate evil of four extra turns for each player at the beginning of every game, complexity which hassles us immediately in exchange for an uncertain future benefit.  And (2) we aren't even sure why the setup phase leads to unbalance, supposing it does, so even though the proposed procedure is completely logical, we can't sure it would fix the unbalance if it ever emerged.
 
I'm glad that Omar left the setup phase in it's current simple, pure form.  Are you glad too?
« Last Edit: Apr 25th, 2013, 8:33am by Fritzlein » IP Logged

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