----- Original Message -----
From: "Magnus Persson" <[EMAIL PROTECTED]>
To: <computer-go@computer-go.org>
Sent: Wednesday, December 06, 2006 9:19 AM
Subject: Re: [computer-go] KGS Computer Go Tournaments
Quoting Don Dailey <[EMAIL PROTECTED]>:
I would love to see such a tournament, but the UCT programs could not
take full advantage of the extra time. As you see, we run out of
memory after a minute or two!
Valkyria can prune the tree but not indefinetly. I think it would at least
be
able to think for an hour per move. But there is a risk that the cure
(pruning)
hurts it such that it playing strength starts scaling poorly with
increased
thinking time.
-Magnus
I do not understand why they run out of memory in such a short time. E.g.
MoGo calculates 1100 Episodes/sec on 19x19. If one assumes 1 episode is 400
moves, its max. 440 KPositions/sec.
In 2 minutes its about 60 MPositions. This is a very conservative upper
bound. As far as I have understood it the MC-part not stored, only the
UCT-part. Additionally nodes are visited several times and there are
transpositions. But even with this upper-bound, if one uses 16
Bytes/Position its still "only" 1 GByte of RAM.
If one assumes a ratio of 1:10 between UCT and MC nodes, its only 6
MPositions or 100 MBytes which must be stored. In my paper-design 200 MBytes
should be enough to run practically "forever".
Maybe there is a logical flaw in my calculation. In this case it would be
nice if one of the UCT-programmers explains were all this memory is used.
Note: If one uses for each small chunk of memory malloc() there is a
considerable overhead. With STL it gets worse. But STL is anyway no option
for a speed and memory critical programm. It should be relative trivial to
write an efficient memory handler.
Chrilly
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