Author: Andreas Herrmann
Date: 06:58:35 09/14/00
Go up one level in this thread
On September 14, 2000 at 08:38:31, Andrew Williams wrote:
>On September 14, 2000 at 05:25:32, Andreas Herrmann wrote:
>
>>On September 13, 2000 at 17:12:07, Andreas Herrmann wrote:
>>
>>>Hello,
>>>
>>>i want to include pawn hash tables in my chess program holmes, but i don't know
>>>how i have to calculate the hash index and the hash key.
>>>I think the hash index of the position will only calculated with the pawns on
>>>the board like the following,
>>>
>>>for (pos=A1;pos<=h8;pos=pos+1) {
>>> if (figure[pos]=pawn) {
>>> PawnHashIndex = PawnHashIndex ^ RandomIndex[pos].index;
>>> }
>>>}
>>>
>>>is this right??
>>>
>>>How can i get a good hash key? What have i calculate with xor?
>>>
>>>Thanks for each information.
>>>
>>>Andreas
>>>
>>>
>>>www.wbholmes.de
>>
>>Hello again,
>>
>>the links from Ricardo are a good information source, but i found nothing about
>>pawn hash tables, only normal hash table and that's not new for me.
>>
>>My question is how can i get a good hash key for collision check in the pawn
>>hash table.
>>Is a XOR combination with a random figure enough? Or is it not so difficult than
>>i am thinking?
>>
>>Andreas
>
>Yes. I've always used a 64-bit integer derived in just the way you describe.
>I don't know if 32-bits would be sufficient, as I've never tried it.
>
>Andrew
Ok a 64-bit integer is of course much better against hash collision than a
32-bit. I will try to implement it with a 64-bit interger.
thanks
Andreas
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