Author: Dann Corbit
Date: 12:08:33 07/17/00
Go up one level in this thread
On July 17, 2000 at 15:06:35, Tom Kerrigan wrote:
>On July 17, 2000 at 13:56:46, Dann Corbit wrote:
>
>>On July 17, 2000 at 13:40:28, Tom Kerrigan wrote:
>>
>>>I've had a number of requests to implement 3-fold repetition detection in TSCP.
>>>It's also clear that TSCP would do better in tournaments (although that isn't
>>>the goal...) if it could detect these draws.
>>>
>>>So the question is, is there an easy way to do the detection?
>>>
>>>In my "strong" program, I just compare hash keys. But TSCP doesn't keep hash
>>>keys and I have no intention for it to do so. So is there another way to do it?
>>>
>>>Thanks in advance.
>>
>>Just keep an ordered list of the actual EPD positions as the game moves along.
>>If you see one occur twice, increment a counter. If you see it three times --
>>draw. Since there are going to be less than a thousand positions during a game,
>>the storage cost will be very small, especially if you keep them in binary
>>format. When you insert a new element, the counter is one. Pretty easy.
>>
>>You could use and EPD bolt-on like the one on my ftp site which will keep your
>>part of the code simple, but requires a C++ compiler. You could retain a C
>>interface to the C++ functions by doing extern "C" {} wrappers.
>
>Doing this at every node would be much worse (slower & memory intensive) than
>just incrementally updating hash keys.
Not at every node. Only at the move played. You just look at the list. But if
you make a hash table, you are right -- hash keys are better. Of course, the
hash key could be over-written. The move list can't.
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