Re: Advice on evaluation

[Eric Pettersen <pett@xxxxxxxxxxxx>]

David Fotland wrote:
>I'd like some advice before I make a huge code change in Many Faces of Go.
>
>Up to now, the evaluation in MFGO is not aware of what color is moving
>next.  Group strength is based just on eye shape, running ability, etc,
>not on who moves next.  For territory, I evaluate the minimum territory
>for each side.
>
>I'm thinking about evaluating differently based on who is moving next.
>For group strength today, I have a single value.  I'll have two values
>after this change:  one for white to move, and one for black to move.
>I can look at the difference between those values to see if a group is
>worth attacking or defending.

My program (gottaGo) already kind of does this.  One of the life/death  
values it can assign to a group is "killable"; this value means that the  
group can be killed if the opponent attacks it before a defending move is  
played.  Conversely, the group is alive is a defending move is made before  
the group is attacked.

When gottaGo (a fixed-depth search program) reaches a terminal node for  
evaluation, it notes what groups are killable.  It then "auctions" the  
groups on the list off; it assumes that the side to move will kill/save the  
largest value group, the other side will then kill/save the next largest  
value group, etc. until all killable groups are taken.
---
			Eric Pettersen
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