Consider this as tentative, since I heard it about 3rd-hand, but I believe the 
number of processors used to have been 3000.


Congratulations to the Mogo team; good luck improving your program to deal with 
the ladder and life-and-death issues.

Looking forward to further information!

I have always wondered if AMAF is a feature or a bug. There are many situations 
where the order of moves is crucial; A before B wins, B before A loses; ladders 
are a classic example where the ordering of moves is utterly important. AMAF 
seems to assume that order doesn't matter. Of course, there are many other 
positions where this assumption is true; that is why it sometimes yields an 
improvement in processing speed, but it seems risky.

Ladders are also a classic case where two patterns can look very similar, but 
be very different. When you capture a ladder, you are in a very good position. 
But if the stones under attack have just one extra liberty, the position may 
"look like" a ladder, but your target will escape, and your stones will be full 
of cutting points; the proper evaluation for that position would be much 
harsher. More generally, whenever I see a Monte Carlo program lose, it is 
usually a semeai where being one liberty behind or one ahead makes all the 
difference. We call these "capturing races" in English for a reason; being 
ahead or behind by one liberty matters a great deal. To make life interesting, 
there are "loose ladder" constructs where an extra liberty does not help the 
fleeing stones; they still get corraled and captured.

These corner cases are tough, but many games hinge on correctly reading out the 
exact consequences of life-and-death struggles.

Terry McIntyre <[EMAIL PROTECTED]>


"Go is very hard. The more I learn about it, the less I know." -Jie Li, 9 dan

> On Mon, 2008-09-22 at 13:59 +0200, Magnus Persson wrote:
> > Quoting Mark Boon :
> > 
> > > Playing out that fake ladder in the first game meant an instant loss.
> > > Surprising. And embarassing. Any information on the number of
> > > processors used?


      
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