Hi,
I have been silent for a long time here on the list but I have had
Valkyria play 9x9 correspondence go, all along on OGS and Little Golem.
I know it means very little but Valkyria just reached 9Dan after the
last won game. Simply because the rank gained for each win on LG is a
little too large for sound ranking system.
http://www.littlegolem.net/jsp/info/player.jsp?plid=22065
On OGS
http://online-go.com/user/view/34958/Valkyria9
it would take many years to reach a similar ranking although the win
rate of Valkyria and number of played games is about the same.
Valkyria on correspondence games uses a special search mode. It uses a
50 MB hash table with 4 million entries storing hash, best move and tree
search size (encoded as N, where Number of playouts > 2^N.
Valkyria is aggressively selective and will produce very different
search trees if it started from scratch in the same position. Therefore
to overcome randomness the search tree is erased as soon as the number
of hashtable misses >> hashtable hits. For a difficult move in a
correspondence game I let it search 1-10 hours, sometimes even more. The
search usually resets 5 to 20 times. The move selected is the move that
has been selected most of the time. Thus moves that are caused by random
events in selective search are weeded out.
The result is really robust play but I think there are still huge
biases in evaluation that cannot be overcome by search, so even if the
opening book is pretty strong there are probably a lot of lines that are
far from strongest possible play. And often have a feeling that biases
drives it towards losing positions but wins because of tactical mistakes
of opponents.
Anyway it would be fun to have some more competition in for example the
OGS Alan Turing tournament that is open for go programs and also players
using programs.
See
http://online-go.com/tournaments/2490/-/Alan%20Turing%20Nines%20Title%20Tournament%202013
Best
Magnus Persson (Valkyria)
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