RE: computer-go: Scoring

["Grajdeanu, Adrian" <adrian.grajdeanu@xxxxxxx>]

Tom, I'm confused to say the least.
Your description is detailed enough to catch my attention, yet not detailed
enough to enlighten me.


> DEFINITIONS:
> A 'white score area' is a continuous area of non-white intersections.
> plus the intersections of the bordering white groups.

What is a continuous area? A set of intersections adjacent to each other? In
other words, strings of non white?
What do you mean the intersections of the bordering groups? The white
intersections or the interior points, or both?
How do you handle the edges of the board?


> A white score area and a black score area 'intersect' if they
> share any of the same intersections.

I'm all right with that.


> A white score area is said to be 'contained' if it
> intersects with one, and only one black score area.

What if on the board there are only two fully enclosed territories that
don't touch borders, one black and one white. Do I understand right that
either one is enclosed? For each such one defines the 'internal' score area
and the 'external' score area and the external encloses the opponent's
'internal' score area.


> A white score area is said to be 'non-containing' if
> it does not intersect with any contained black score area.

What if you have two white territories, close to each other, but not
touching. And one black scoring area that intersects them both. The black
scoring area is not contained, for it doesn't intersect with only one white
scoring area. Then both white scoring areas are non containing. What if the
edge of the black scoring area is thick and has internal territory?



> A white score area can also be said to score
> so long as it is non-containing, and so long as it does
> not intersect with any non-containing black score area.

What if the black scoring area is containing? Does it mean that the outer
white are is scoring? What if the containing black area is surrounded by
groups that are actually dead?


> Dame + forced connections:
> (not really essential, but...)
> 
> Any empty intersections that are not within a scoring
> score area for either side are dame.
> 
> If there are any [white+dame] groups that border only one empty,
> non-dame intersection, then that intersection may not
> be scored for white.

You talk about groups now. Are they strings (adjacent intersections) or
unseparable sets of such strings? Can you give an example of such empty
non-dame intersection?


> 2 possible scoring methods:
> 
> 1. Chinese style
> The final score for each player is one for each intersection
> in each of his/her scoring score areas, plus one for
> each intersection of his/her color that is not in
> an opponents scoring score area.
> 
> 2. Japanese style
> Any stone that lies in an opponents scoring score area
> is added to the opponents prisoners.
> The final score for each player is one for each intersection
> in each of his/her scoring score areas plus the
> number of prisoners they have captured.
> 
> 
> 
> I tested this on 50 random games, from Dave Dyer's
> score-annotated collection.
> (many thanks, dave :)     )
> 
> Its performance was:
> 
> 19/50 scored exactly the same.
> 36/50 scored to within 1 point difference
> 40/50 scored to within 3 point difference
> 
> In all the cases that were incorrectly scored, the correct
> result could be gained by playing on just a few stones more.

great result. Would you please better explain your proposal? Or probably it
would be most unambiguous if you allowed a glimpse at the code that you
tested.


> 
> 
> Using the chinese scoring method the players can be assured
> of the correct result, because if the algorithm is going to
> give an incorrect result either player can play on, removing
> his opponents dead stones without penalty.
> 
> If all the dead stones are removed, and dame filled,
> the algorithm will score as tromp/taylor,
> provided an additional constraint is added to prevent
> scoring of seki positions:
> * A white score group may not score if it consists of
> exactly two empty intersections, and at least one black intersection
> (similarly for black)

What is a white score group? We've only talked about white scoring areas?
What if the battling groups that are in seki aren't quite there yet? Maybe
they contain more then two isolated dames between them, but the players
didn't bother to fill those in? Doesn't this still qualifies as seki?
Top left corner:
.000.x0
xx.xxx0
0xxx000
00000



Then in general I'm wondering how could such thing score accurately if it
doesn't make distinction between alive and dead stones. How does it treat
differently a group that has only one eye as opposed to one that has two
eyes. How does it recognize a group w/ only one eye, but a large enough one
that can be divided into two?