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Subject: Re: A math problem for the experts....

Author: Uri Blass

Date: 23:54:32 10/02/01

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On October 02, 2001 at 20:52:13, TEERAPONG TOVIRAT wrote:

>
>Dear Dr.Hyatt,
>
>I think the number of total _possible_ positions in chess is beyond
>the question. However,I'd like to know how they calculate it ?
>
>A few months ago,I tried to work out the number in _checkers_
>game. My logical assumption is that if the hash signature is too
>small there would be a high incidence of type 1 collision and if
>the hash signature is large enough the collision would be 0.
>So,my experiment started with 32 bit hash table ,after 1 million
>entries are fully occupied I started counting the incidence of
>type 1 collision. Each time I got type 1 error,I increase another
>bit to the hash table.I saw the incidence is lowered by half too.
>Until one point the incidence is zero ,of course after a few
>games test.
>
>Could I claim that at that point the hash signature is approximately
>equal to the number of legal(possible) positions?

I do not know what is type 1 collision and I also do not understand what hash
tables can do with the number of legal positions because it is known that the
search trees of programs contains only a very small part of the number of legal
positions.

Uri



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