Re: [gnugo-devel] Opponent follow-up value and group connection

[Arend Bayer]

On Sat, 10 May 2003, SP LEE wrote:

> Then at move 166, GNUGO played M6, letting the lower right corner group T7
> dead by white O6, losing about 30 points. It is interesting that the owl
> analysis of T7 is completely correct. It said that T7 is dead if white plays
> O6 and the defend of T7 is possible at O6.
>
> Below is the top moves GNUGO considered:
>
> Top moves:
> 1. M6  36.76
> 2. O6  36.11

>
>   M6: owl attack/defend for L6
>   M6:   2.83 (followup) - threatens to capture M5
>   M6: 11.17 - change in territory
>   M6: 3.87 - strategic effect on L8
>   M6: 8.17 - strategic effect on N7
>   M6:   3.94 - L6 strategic value already counted - A.
>   M6: 8.04 - strategic effect on K5
>   M6:   2.83 - total followup value, added 0.00 as territorial followup
>   M6: 1.42 - added due to followup (2.83) and reverse followup values (0.00)
>   M6: 3.35 - shape (shape values +2.00(1) -0.00(0), shape factor 1.102)
>   M6: 0.74 - connects strings (connect value 7, shape factor 0.149)
> Move generation values M6 to 36.75
>
>   O6: owl attack/defend for T7
>   O6: 29.81 - change in territory
>   O6: 3.13 - strategic effect on N7
>   O6: 2.48 - strategic bonus for T7
>   O6:   4.33 - total followup value, added 4.33 as territorial followup
>   O6: 2.16 - added due to followup (4.33) and reverse followup values (0.00)
>   O6: -1.79 - shape (shape values +0.00(0) -1.00(1), shape factor 0.952)
>   O6: 0.31 - connects strings (connect value 3, shape factor 0.061)
> Move generation values O6 to 36.10

> I would think if a group is dead and worth 30 points, GNUGO must consider it
> seriously.

Yes, the problem here is that the strategic valuations of M6 got a bit
confused. One problem is the dragon at K5. It can either connect to
H6 or to K9, and so M6 should get hardly any "strategic effect" bonus for
that.

Also the shape values don't exactly help here.

Arend