Re: computer-go: Perl Module for next move.

[Daniel Bump <bump@xxxxxxxxxxxxxxxxxx>]

> I am wondering how accurate is the scoring using --score end? As gnugo is
> generating moves till the end of the game, the evaluation is only as
> accurate as gnugo is able to play perfectly that rest of the game. With NNs,
> they may end the game even after let's say 10 moves. How will gnugo do a
> --score end? For these considerations I am more inclined to go for --score
> last.

If you use --score end then GNU Go uses the Bouzy 5/21 definition
of territory and computes the score. This is also what who_wins
does to generate and report a score at the end of the game.

This algorithm is pretty good but it can make mistakes. At the end
is a game where GNU Go computes the wrong score. You can see what
happens by running gnugo --moyo 1 on the file. Because the 3-3
point is open, the corner is not recognized as territory. The
reported score is therefore wrong.

In the middle of the game I think the 5/21 based algorithm is
pretty good and could be used as a basis for decision making.
(Are we ahead? If so, play cautiously.)

Yet GNU knows that a 3,3 invasion cannot live.

This is actually fairly unusual. In most games all territory
is found. But examples like this show that the scoring function
needs work.

This game was sent to us by Mike Charlton in November.

Dan


(;GM[1]FF[3]
RU[Japanese]SZ[9]HA[0]KM[5.5]
PW[Rook]
PB[Mike]
GN[Rook (W) vs. Mike (B)]
DT[2000-11-15]
SY[Cgoban 1.9.7]TM[30:00(5x1:00)]
RE[B+11.5]
;B[fd]BL[1790];W[dd]WL[1800];B[ef]BL[1781];W[fc]WL[1800];B[gc]BL[1770]
;W[ec]WL[1799];B[gd]BL[1766];W[cc]WL[1799];B[de]BL[1760];W[ce]WL[1797]
;B[cf]BL[1756];W[be]WL[1796];B[fb]BL[1746];W[bf]WL[1795];B[cg]BL[1736]
;W[ee]WL[1794];B[fe]BL[1727];W[df]WL[1793];B[dg]BL[1708];W[eb]WL[1792]
;B[ga]BL[1687];W[bg]WL[1791];B[bh]BL[1685];W[de]WL[1789];B[eg]BL[1676]
;W[ag]WL[1789];B[ah]BL[1666];W[ea]WL[1788];B[ff]BL[1630];W[fa]WL[1788]
;B[gb]BL[1615];W[ed]WL[1788];B[tt]BL[1603];W[tt]WL[1787];
TW[aa][ba][ca][da][ab][bb][cb][db][ac][bc][dc][ad][bd][cd][ae][af]
TB[ha][ia][hb][ib][hc][ic][hd][id][ge][he][ie][gf][hf][if][fg][gg][hg][ig][ch][dh][eh][fh][gh][hh][ih][ai][bi][ci][di][ei][fi][gi][hi][ii]
C[The game is over.  Final score:
   White = 16 territory + 1 captures + 5.5 komi = 22.5
   Black = 34 territory + 0 captures = 34
Black wins by 11.5.
]
)