I guess you missed my message.

I solved this by comparing the current node with its ancestors in the  path.
On each walking down the tree, I pass the list of nodes in the same path.
Then I check whether the current node already appear in the path. If yes, I
assign a loss there. To speed it up, I only check the current node against 6
nodes before it.

It is not perfect or accurate solution for the issue, but it solves the
problem at hand.



On Fri, Jul 11, 2008 at 12:23 PM, John Fan <[EMAIL PROTECTED]> wrote:

>  I had the same issue in UCT tree. What I did is to check if the current
> node is a ko move, then compare it with its latest 6 ancestors. If any match
> is found, then consider the move is a loss. So it cuts off the infinite
> loop.
>
>
> On Fri, Jul 11, 2008 at 12:08 PM, Peter Drake <[EMAIL PROTECTED]> wrote:
>
>> My sense is that most programs ignore superko except for checking right
>> before a "real" move (as opposed to a playout move) is played.
>>
>> The way out of the infinite loop is to set a maximum number of moves in a
>> playout; abort the playout if you reach this threshold.
>>
>>
>> On Jul 11, 2008, at 9:03 AM, Jason House wrote:
>>
>>  I tracked down a rare hang/crash in my bot and I'm curious how others
>>> handle this.
>>>
>>> I use simple ko state as part of my hash lookup, but I don't use super
>>> ko. I can't store the whole graph history because then there would be no
>>> transpositions at all. I can't really update legal moves to exclude super ko
>>> because the super ko legality changes based on how a node is reached.
>>>
>>> In particular, a deterministic algorithm like UCT can get caught in an
>>> infinite loop. My random playouts may take a bit longer from super ko, but
>>> it gets quickly resolved.
>>>
>>> Sent from my iPhone
>>> _______________________________________________
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>>> [email protected]
>>> http://www.computer-go.org/mailman/listinfo/computer-go/
>>>
>>
>> Peter Drake
>> http://www.lclark.edu/~drake/ <http://www.lclark.edu/%7Edrake/>
>>
>>
>>
>>
>> _______________________________________________
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>> http://www.computer-go.org/mailman/listinfo/computer-go/
>>
>
>
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