Author: Dann Corbit
Date: 00:07:18 07/29/03
Go up one level in this thread
On July 29, 2003 at 02:52:43, Russell Reagan wrote:
>On July 29, 2003 at 00:28:46, Dann Corbit wrote:
>
>>If the position is not in the hash table anywhere (ignoring depth), no need to
>>search -- you have not seen it yet.
>
>Hi Dann,
>
>I'm confused :-/
>
>What do you mean by "ignoring depth"?
Well, you are right. For a repetition hash table no need to bother storing any
depth information. It's irrelevant.
>
>Isn't it possible for a position to not be in the hash table and still have
>occured in the game (ex. if the position was overwritten)?
Sure. But it's rare. If you are going to use a hash table to detect
repetitions you will have to:
1. Live with an occasional blunder due to overwrite
OR
2. Make some rule like "NEVER overwrite a position tagged as pv"[*]
OR
3. Chain the darn thing
OR some such.
I suspect most people do #1.
[*] implies that the hash table stores at least one bit to say a position is in
the pv {and pv's do change...}
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