[computer-go] 10k UCT bots

[Don Dailey]

Álvaro Begué wrote:
> On Tue, May 13, 2008 at 2:28 PM, Mark Boon <tesujisoftware at gmail.com> wrote:
>   
>> On 13-mei-08, at 15:08, Jason House wrote:
>>
>> The range of the random number is reduced by one after each failed lookup.
>> Shuffled data has no impact on future use of the array of empty points.
>>
>> OK, I understand now why a point at the end (or beginning) is a little less
>> likely to be picked. Although I still have doubts whether that will lead to
>> a noticable bias, I'll try to think about it.
>>     
>
> I don't care much about it being noticeable. This thread is about
> putting bots on CGOS that use a reproducible algorithm, to help people
> detect bugs in their implementations. As part of specifying what these
> bots do, we should all pick the next move in a playout using the same
> criteria. If we agree to use uniform distribution among empty
> non-eyeish points, that's what should be implemented.
>   
I agree with this.   If we get too clever we lose confidence that we are 
comparing apples to apples by risking bugs and making assumptions that 
may not hold.

- Don


>   
>> I would imagine moving an illegal point towards the end and only start
>> including it when the other 'legal' moves run out can lead to terrible bias
>> however because they may not remain illegal for very long and actually
>> become important points to play. A ko-point is probably the most extreme
>> example of that.
>>     
>
> I don't think you understood the algorithm. The eyeish point is
> removed from the lottery only for picking this particular move, not
> for the rest of the playout.
>
>   
>> Anyway, I don't bother to order the empty-point-list or scramble them in any
>> way prior to the game. So the first point is the 1-1 point and the last is
>> the 19-19 point (or whatever boardsize you're playing) so I have no qualms
>> about those moves being a little less likely to be played. Or even a lot
>> less. I think it would actually be beneficial.
>>     
>
> Reproducibility was the point, not strength of the bot.
>
>   
>> If this asymmetry really bothers you, you could very easily fix this by
>> wrapping the search around. There's no asymmetry in a circle.
>>     
>
> That doesn't fix anything.
>
>
> Álvaro.
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