Magnus Persson: <[EMAIL PROTECTED]>:
>Quoting Don Dailey <[EMAIL PROTECTED]>:
>
>> Yes, UCT is easier to use with multiple CPU's because with additional
>> processors alpha-beta programs do wasted work, unless you are talking
>> about theoretical programs with perfect move ordering, which you aren't.
>
>Nice that all is clear about alpha-beta programs.
>
>But... does not UCT with additional processors waste a lot of  
>simulations because what would be the optimal path through the search  
>tree depends on the threads that have not finished yet?

Yes, UCT does.  From my recent experiments with a delay 
line (a fixed size FIFO queue) between a UCTsearcher and an MC 
simulator with RAVE against GNU Go 3.7.11 level 0 on 9x9 (single 
thread):

delay   #po     wins    games   winning rate    ELO     1 sigma of wr
0       1,000   721     2,000   36.05%          -99.6   1.07%
1       1,000   721     2,000   36.05%          -99.6   1.07%
2       1,000   690     2,000   34.50%          -111.4  1.06%
3       1,000   663     2,000   33.15%          -121.8  1.05%
5       1,000   642     2,000   32.10%          -130.1  1.04%
10      1,000   522     2,000   26.10%          -180.8  0.98%
20      1,000   412     2,000   20.60%          -234.4  0.90%
50      1,000   82      2,000   4.10%           -547.6  0.44%

Hideki

>Some people reported that more processors helps a lot on large boards,  
>whereas on smaller one there is not much gain.
>
>-Magnus
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[EMAIL PROTECTED] (Kato)
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