Yes it is tricky I think my main idea (and I think similar ideas can
been found in a couple of papers) is to check for unexpected super ko
violations and then one has to mark the path that led to that
violations as "dirty" and create a new line in the collision node so
that dirty variations has there own node linked to the original
transposition node in a linked list, and there is a parent pointer
that is used to identify the right node in the linked list. This is
what I remember but details were hairy because of the many ways this
could happen.
But most of the problems goes away if one uses a good hashing scheme
that also makes different capture histories different. I think Erik
vand Der Werf has written some good stuff on this issue because it
becomes extremely import when you try to solve game on small boards.
-Magnus
Quoting Michael Williams <[email protected]>:
Keeping a real tree is of course tivial. I guess you mean a way to preserve
the benefits of transposition while also maintaining admisibility. That
does seem like it would be tricky.
On Fri, Jul 8, 2011 at 9:24 PM, <[email protected]> wrote:
Quoting Michael Williams <[email protected]>:
The Valkyria tree is not a pure tree, because a node can have several
parents if more than one sequence leads to a position.
Best
Magnus
I think this is common, but inadmissable in the strictest sense,
right? Because the optimal action for a node depends on it's history of
positions thanks to the super ko rule.
What was the word Don used for techniques like this? I mean techniques
that
are not going to lead to perfect play given infinite time and memory.
Yes, you are right. For the next rewrite of Valkyria I actually think i
rediscovered some algorithm to solve this but it is painfully complicated to
implement.
Luckily it is extremely rare that affect play (I think).
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