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Topic: bot functions speed (Read 7882 times) |
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Hippo
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Arimaa player #4450
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Re: bot functions speed
« Reply #45 on: May 16th, 2011, 9:02am » |
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on May 16th, 2011, 6:48am, JimmSlimm wrote:Ah, thanks lightvector for that idea.
Yes Swynndla I am currently doing width-first |
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I cannot beleive it could work ... expanding to 2 or at least 3 full turns must lead to consumption of the whole memory.
I would expect expanding to full width only in one branch.
Of course even more (at least space) effective method does not need to keep full expansion of a level, but generating positions/moves on demand.
The problem with avoiding search of repeated positions could be more difficult when positions are generated on several levels of search concurently.
(Repetition avoiding hash table(s) need several active histories).
I still use the original jdb's engine, but it's step based except the root level so expanding full width of at most 185 moves (except the killers) is not problem.
I am still not sure which option to chose. Generating moves on demand has advantage when the generation is interrupted due to cut in search.
Generating all the moves allow their sorting prior to further search. So it allows more efficient cutting.
So probably on bottom search level generating on demand is preferable while on higher levels generating all the moves (and their sorting) is better.
Generating on demand "presorted" is preferable.
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lightvector
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Re: bot functions speed
« Reply #46 on: May 16th, 2011, 9:52am » |
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I also copy the board, because it's easier. I don't have to track all the metadata for undoing in the presence of captured pieces.
Optimization of all of this stuff is fine, but as long as you're doing something "not terrible", I've found that it doesn't matter. The bottleneck for me at least is evaluation. I could do any number of different things to optimize move generation, board copying, etc, in the search, and it wouldn't make that big of a difference, since only a small fraction of the time is taken by these things, compared to evaluation.
Beware of premature optimization.
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rbarreira
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Re: bot functions speed
« Reply #47 on: May 16th, 2011, 10:56am » |
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on May 16th, 2011, 9:52am, lightvector wrote:I also copy the board, because it's easier. I don't have to track all the metadata for undoing in the presence of captured pieces.
Optimization of all of this stuff is fine, but as long as you're doing something "not terrible", I've found that it doesn't matter. The bottleneck for me at least is evaluation. I could do any number of different things to optimize move generation, board copying, etc, in the search, and it wouldn't make that big of a difference, since only a small fraction of the time is taken by these things, compared to evaluation.
Beware of premature optimization.
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In general you are definitely correct, but sometimes profiling the code can be deceptive. As an extreme example a program may have a piece of code which doesn't take that long to run, but which causes the whole cache to get filled with trash. The slowdown will show up in other parts of the code.
For this specific case on copying vs unmaking moves, originally I saw benchmarks from Robert Hyatt with his chess program which indicated that as the number of threads goes up, the unmaking approach starts to get faster. I was unable to reproduce this with my Arimaa bot, but I don't think I tested with as many threads as he did, since I usually only test it on a 6-core CPU.
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Druzil
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Re: bot functions speed
« Reply #48 on: May 16th, 2011, 7:09pm » |
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JimmSlimm how are you accessing so much memory with C#. Even with x64 CPU and x64 OS the maximum memory available is ~8.7GB
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JimmSlimm
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Re: bot functions speed
« Reply #49 on: May 17th, 2011, 6:44am » |
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on May 16th, 2011, 7:09pm, Druzil wrote:| JimmSlimm how are you accessing so much memory with C#. Even with x64 CPU and x64 OS the maximum memory available is ~8.7GB |
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I don't know, task manager sais >10gb is used by the bot process sometimes
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Swynndla
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Re: bot functions speed
« Reply #50 on: May 18th, 2011, 9:16pm » |
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on May 16th, 2011, 9:52am, lightvector wrote:| Optimization of all of this stuff is fine, but as long as you're doing something "not terrible", I've found that it doesn't matter. The bottleneck for me at least is evaluation. I could do any number of different things to optimize move generation, board copying, etc, in the search, and it wouldn't make that big of a difference, since only a small fraction of the time is taken by these things, compared to evaluation. |
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I like what you say. Please keep up the clear, logical & to-the-point posts! (I'm learning a lot.)
Will you be making Sharp 2012 multi-threaded (to take advantage of the multiple cores), or will you be concentrating on evaluation & pruning?
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| « Last Edit: May 18th, 2011, 9:18pm by Swynndla » |
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