[computer-go] 10k UCT bots

[Don Dailey]

Mark Boon 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 believe there is any bias based on where a good point is, only 
where the bad points are.   Because you can think of this list of empty 
points as a circular array,  where no particular location is any more 
significant than any other.

>
> 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 had a "bug" in my program that may have been an actual improvement.   
I did not always resurrect empty points that were eyes.   I went ahead 
and fixed this and didn't try to assess whether it was a "good bug" or 
not but I didn't notice any improvement.  The net effect was that if a 
move was an eye move that you shouldn't move to,   and the opponent 
moved to a diagonal,  the program still would not move to it.   That's 
probably sound in some cases and not in others.

>
> 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.
>
> If this asymmetry really bothers you, you could very easily fix this 
> by wrapping the search around. There's no asymmetry in a circle.
>
> Mark
>
>
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