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Subject: Re: Hashtables: is larger always better?

Author: Antonio Dieguez

Date: 17:07:43 09/24/01

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hi Thomas!

I did try before with 32 bits in amyan, and I think it only finished ONE game
without crash!(when playing illegal move sometimes it will crash), may be I had
bad random numbers also but anyway 32 bits is maybe too low. Do you check if the
hash move is legal? you could do it and see.

>well, I am doing it quite similar to Antonio I think, I have two 32 bit
>variables... One is the HashKey and the next one is the HashIndex with which I
>compute the index in the table with &... Stored is only the HashKey in the
>table.
>In the book I've read first about how to do hashtables it was explained that
>way... I have tried once to change this to a single 64 bit variable, but it was
>slightly a bit slower - the comparison of 64 bit variables seems to be to slow
>on current x86-compatibel processors...
>Since I store also EP-information and castling rights in the HashKey and
>HashIndex I have never seen a colission anymore...
>You can say, that is something like a 48 bit - hashkey... When I have only 65536
>positions in hash... usually more then a million, the used hashkey size grows
>with the size of the table...
>
>Greets, Thomas



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