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Topic: Notes about bot_Zombie in Postal Tournament (Read 3493 times) |
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IdahoEv
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Notes about bot_Zombie in Postal Tournament
« on: Mar 1st, 2007, 4:08pm » |
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seanick emailed me earlier today, concerned that zombie had not moved in a couple of days in his game. This is pretty much normal and expected, and I wanted to post in case other players were concerned.
Zombie is playing 15 games with three hours of thinking for each. That means it takes 45 hours for Zombie to cycle through and submit one turn in each game if all his opponents are submitting turns quickly. So in the early stages of the postal tournament, when people are still logging in all the time and submitting turns quickly, expect zombie to burn at least a day of reserve for every turn.
Response time to your moves may improve later in the tournament as other players go a few days without submitting moves, allowing Zombie to ignore those games for a while.
The botman script also cycles through the games in numerical order; the first one is 59204 against arimaa_master. Because I occasionally have to restart the script and it always starts from the top, games early in the list will get more attention and sometimes two moves in fairly short order.
If its operating correctly, you should only see a move every two days or so for now.
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| « Last Edit: Mar 1st, 2007, 4:09pm by IdahoEv » |
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99of9
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #1 on: Mar 2nd, 2007, 12:50am » |
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Are you monitoring the depth that Zombie searches to?
Even though I'm not playing against it, I'd be interested to know how deep it's going.
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Fritzlein
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #2 on: Mar 2nd, 2007, 7:21am » |
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From a glance at the logs, the short answer is that Zombie is searching about 12 or 13 steps deep.
For the opening moves, since the branching factor is lower, Zombie searched more deeply. As the branching factor rises, Zombie may not be able to search as deeply in the midgame.
After part of its thinking time is used up, Zombie decides on an initial step, i.e. it prunes all other first steps apart from its favorite, and continues searching from the second step. A while late it decides on its second step, and continues searching from the third, etc. Since Zombie might search to a depth of 12 steps after having decided on its first three steps, you could say it is searching to a depth of 15 steps, but that is a bit misleading.
I'll let IdahoEv explain the other fancy ways Zombie searches deeper/shallower in some lines. 
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IdahoEv
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #3 on: Mar 2nd, 2007, 12:23pm » |
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This is about right; I've seen zombie search the initial position up to 17 steps deep, but only when its transposition table was much larger than it is now.
Quote:| After part of its thinking time is used up, Zombie decides on an initial step, i.e. it prunes all other first steps apart from its favorite, and continues searching from the second step. A while late it decides on its second step, and continues searching from the third, etc. Since Zombie might search to a depth of 12 steps after having decided on its first three steps, you could say it is searching to a depth of 15 steps, but that is a bit misleading. |
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This is essentially right, but not entirely. Zombie actually generates and searches moves, which may contain a variable number of steps. So occasionally it will select a 2-step move (a push or pull) in which case it will prune both those steps and then begin a new search from two steps later than the last one.
I actually don't think this adds any additional strength - almost inevitably the later positions zombie selects are the same as the next three steps on the branch it found for the first step. And in addition if you're going to search earlier I think you'd like to have the option of altering your move from the very first step; i.e. I think this technique assumes an independence of the four steps that is not really accurate.
I've attempted to change it so that it spent 100% of the turn searching as deep as possible for the first step, and accepted the first four steps from that tree as its move. However, everything I've attempted along those lines resulted in the occasional inexplicable suicide so clearly I'm not quite understanding unic's original search code from Fairy.
Quote:| I'll let IdahoEv explain the other fancy ways Zombie searches deeper/shallower in some lines. |
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Zombie has an extensions mechanic that lets it alter the target depth of a branch based on certain conditions. For example, it won't bother searching as deeply after a suicide move, on the hypothesis that a suicide usually needs to have payoff soon afterwards. After captures it tries to search a little deeper, hopefully generating some of the benefit of a quiescence search. However, the changes in depth are small (only a step or two usually) so I don't think they have a huge effect on zombie's strength.
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| « Last Edit: Mar 2nd, 2007, 12:23pm by IdahoEv » |
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Fritzlein
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #4 on: Mar 3rd, 2007, 9:44pm » |
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Does anyone want to bet on how many games out of fifteen Zombie will win in the tournament? I predict Zombie will win three, for a final score of 3-12. However, I confess that about half of my expected value for Zombie's wins comes for opposing timeouts...
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arimaa_master
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #5 on: Mar 5th, 2007, 3:57am » |
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on Mar 3rd, 2007, 9:44pm, Fritzlein wrote:| Does anyone want to bet on how many games out of fifteen Zombie will win in the tournament? I predict Zombie will win three, for a final score of 3-12. However, I confess that about half of my expected value for Zombie's wins comes for opposing timeouts... |
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I think Zombie has no chance to win against current pairing. Zombie will win only on time.
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IdahoEv
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #6 on: Mar 5th, 2007, 2:56pm » |
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I might lose against Zombie. Not on purpose, but I can still only beat Bomb 50% of the time - bots still often outtthink me tactically.
On the other hand, Zombie just gave me a camel hostage, so...
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chessandgo
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #7 on: Mar 5th, 2007, 3:23pm » |
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Zombie plays quite well, apart from this incentive to endanger its camel without purpose  I would bet on 3 to 5 out of 15 for Zombie ...
Btw, in our two games, Zombie advanced his rabbits willingly and very early ... I knew Zombie was a lot more liberal than Bomb with it's rabbits, but here I'm a bit surprised ... maybe that's a good strategy though
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Fritzlein
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #8 on: Mar 6th, 2007, 2:03pm » |
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on Mar 2nd, 2007, 12:50am, 99of9 wrote:Are you monitoring the depth that Zombie searches to?
Even though I'm not playing against it, I'd be interested to know how deep it's going. |
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By the way, BombP3 (12 steps) thought for about an hour or two per move, while BombP4 (16 steps) seemed to need a day or so per move until it took a week on one move and we gave up on it.
I also looked up what Fotland said about Bomb in the postal tournament two years ago:
on Jan 27th, 2005, 1:08am, fotland wrote:| It doesn't search to a fixed depth. Interesting sequences are searched more deeply. In the postal games it's only looking 8 steps on some sequences, looking 14 steps typically, and looking 25 steps in the more tactical lines. |
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Apparently Zombie is a little slower than Bomb, if it only gets to depth 12 or 13 steps in the time it took Bomb to get 14 steps. However, it may not be that Zombie is slower, so much as that Bomb searched more selectively. Perhaps both of them examine around 300,000 nodes per second.
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| « Last Edit: Mar 6th, 2007, 2:04pm by Fritzlein » |
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Fritzlein
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #9 on: Apr 15th, 2007, 7:56pm » |
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For the first time in the tournament, Zombie is caught up on all of its games, so it has no move to think about. Of course, it eases the time pressure that Zombie has already lost three of the games, so it has only twelve remaining, but it is still set to think for three hours per move. There must have been a brief lull in the collective activity of Zombie's opposition.
In any event, there seems to be no point in having Zombie idle. Does anyone object to raising the thinking time? Technically there are supposed to be no mid-tournament modifications, and Zombie isn't smart enough to think longer for each game on its own initiative. On the other hand, given the pace at which Zombie's opponents are moving, and given the drubbing Zombie is taking in most games, I can imagine that folks would prefer a tougher, slower opponent if anything.
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RonWeasley
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #10 on: Apr 15th, 2007, 8:09pm » |
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Muggles get the same advantage as their games end. On the other hand, if players knew at the beginning that Zombie would get a little stronger as its games ended, they might have chosen to play faster. So I see good arguments either way. I suggest oppoenents who object should do so. Otherwise, let Zombie use the extra time.
IdahoEv, is there any value to you for Zombie opponents to write up a game analysis? It may be obvious where its errors are but maybe not. One common problem I see is a tendency to put the camel on the eighth rank where it is out of play.
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99of9
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #11 on: Apr 16th, 2007, 2:57am » |
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I'm not playing Zombie, but I'll put in my 2c anyway.
I object to changing the thinking time in the middle of the tournament. It's easier to discuss the performance of any bot if it remained identical throughout a game.
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Fritzlein
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #12 on: Apr 16th, 2007, 10:36am » |
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on Apr 16th, 2007, 2:57am, 99of9 wrote:| I object to changing the thinking time in the middle of the tournament. It's easier to discuss the performance of any bot if it remained identical throughout a game. |
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It is reasonable to want to discuss a fixed performance. I'm curious, though, why you are on the opposite side of the issue now, as compared to the issue of letting Gnobot2006CC continue to improve its opening book. Omar didn't want Gnobot2006 to keep updating its opening book with games played after the 2006 Computer Championship, on the grounds that the strength of Gnobot2006 should be a fixed reference point. If I remember correctly, you thought Gnobot2006 should be allowed to keep learning.
You wouldn't object to Zombie managing its time intelligently, with no human intervention, would you? For example, Zombie could easily determine whether it had been through the cycle quickly by looking at its remaining time for the move at hand. The decision could be as simple as this: if Zombie's clock has already run for more than a day, think three hours, otherwise think six hours.
This is important to discuss, because it gets at the intent of the "no modifications" rule. To my understanding, the intent was mostly to insure that the developer wasn't indirectly giving advice to the computer by changing the code from one game to the next. We talked about allowing mid-tournament modifications next year, as long as they weren't game-specific or move-specific modifications. Indeed, one motivation for a developer to enter a bot at all is with the hope that he will be able to improve the bot mid-tournament.
If, however, the intent of the "no modifications" rule is to make the playing strength of the bot easier to assess, that rules out catering to this particular developer motivation.
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99of9
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #13 on: Apr 16th, 2007, 6:28pm » |
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on Apr 16th, 2007, 10:36am, Fritzlein wrote:| I'm curious, though, why you are on the opposite side of the issue now, as compared to the issue of letting Gnobot2006CC continue to improve its opening book. |
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Changing strength in the middle of a game is a bit different to being updated in between games.
Quote:| Omar didn't want Gnobot2006 to keep updating its opening book with games played after the 2006 Computer Championship, on the grounds that the strength of Gnobot2006 should be a fixed reference point. If I remember correctly, you thought Gnobot2006 should be allowed to keep learning. |
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Learning was always intended to be part of the technology and capabilities of Gnobot2006. In that sense, continuing learning represents a fixed technology reference point. Since we're evaluating AI, I wanted to fix the state of the AI. I was not advocating changing the software at all. Omar has a different definition of what needs to be fixed (and was also worried about ownership issues).
Quote:| You wouldn't object to Zombie managing its time intelligently, with no human intervention, would you? |
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Not at all.
Quote:| We talked about allowing mid-tournament modifications next year, as long as they weren't game-specific or move-specific modifications. |
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I'm actually open to that if it is a policy from the start. Then we would just accept the fact that we are measuring something different.
Here it would be a weird hybrid where some games are played in full at constant strength, and other games get up to some arbitrary move and then change (perhaps more than once). What will we learn? What will the developer learn, without picking through exactly which move the switch(es) occurred on?
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Fritzlein
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Re: Notes about bot_Zombie in Postal Tournament
« Reply #14 on: Apr 16th, 2007, 10:33pm » |
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on Apr 16th, 2007, 6:28pm, 99of9 wrote:| What will we learn? What will the developer learn, without picking through exactly which move the switch(es) occurred on? |
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Oh, well, we might learn whether Zombie plays any better at six hours per move than at three hours per move. And it wouldn't be too hard to write down what all the move numbers are on the day of the change.
But honestly, the general point about allowing changes in order to give developers an opportunity to learn more was directed mostly towards next year, when the limits to the in-tournament modifications can be clearly spelled out in advance. Right now I wasn't thinking so much about what we can learn from increasing Zombie's time control. For the current tournament my thought was more about giving the human players as much of a challenge as possible with Zombie on a single computer.
Maybe others feel differently, but I personally would love to play against a bot running on a supercomputer, just to see if I could still win. I remember two years ago hoping that Fotland would increase Bomb's thinking time as much as possible, and being sorry he only raised it from two hours per move to three hours per move. I wanted to humiliate Bomb at maximum power!
Hmm... I just looked at the discussion of the 2005 Postal Tournament and found a couple of interesting quotes. 
on Jan 27th, 2005, 5:47am, 99of9 wrote:| Regarding rules of the tournament - I have no idea, but I don't think changing the time control is really a change of algorithm. |
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on Jan 28th, 2005, 5:49pm, omar wrote:| I don't see any problem with allowing bomb to run for longer on each move. You still are limited by the time control of the game and using one computer to handle all the games. |
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But anyway, even if extending the thinking time is considered legal by precedent, I shouldn't talk so much about what I want for Zombie. I'm not even playing against Zombie, so it doesn't affect me at all, besides which it is IdahoEv's bot, not to mention IdahoEv's computer. I'll shut up now. 
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