RE: [computer-go] Computer Go hardware

["David Fotland" <fotland@xxxxxxxxxxxxxxx>]

For me it is not philosophical.  It is the result of experiment.

The obvious way to use more CPU power is to search more moves from the
list of possible moves (assuming they can be ordered).  The problem is that
many positions have very similar heuristic evaluations, even though strong
players
would evaluate them differently.  An example.  Say there is a position where
I know
there are three reasonable moves, and my move generation heuristics generate
those
three moves.  If I use more CPU speed to look at additional moves, I risk
including
to truly bad move that the the evaluation function won't recognize as bad.
Many bad moves
are bad because of consequences that are not apparent for dozens of moves.

Another example.  If a single stone is unstable on the side on the third
line, a 2 point
jump is almost always a good move.  Sometimes there are better moves, but
most other local
moves will be much worse.  If the move generator only generates the two
point jump locally,
I know it will make a good local move.  If I allow other moves, it will
sometimes make a move
that takes a big loss due to incorrect evaluation.

I know from experiment that if I include extra moves without carefully
updating and testing 
the heuristics, that it plays worse go.

Chess programs don't have this problem since they already search every legal
move, so more
time gives deeper search, which increases strength.

I can use more time to do bigger tactical searches, or more life and death
reading.  This
reading is already accurate enough that spending more time on it makes
negligable difference
to the program strength.  My customers don't like levels that are slower but
not noticably 
stronger :(

David

> -----Original Message-----
> From: computer-go-bounces@xxxxxxxxxxxxxxxxx 
> [mailto:computer-go-bounces@xxxxxxxxxxxxxxxxx] On Behalf Of chrilly
> Sent: Monday, October 18, 2004 11:50 PM
> To: computer-go
> Subject: Re: [computer-go] Computer Go hardware
> 
> 
> >I'd rather have a strong program that doesn't use all 
> available memory 
> >and CPU power than a weak program that uses all available 
> resources :)
> >
> >David
> 
> Thats probably the main philosophical difference between 
> chess and Go-programming. In chess one uses all the available 
> resources for the best possible program.
> 
> Chrilly
> 
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> 

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