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Subject: Re: HashTable upper_bound worthless ?

Author: Larry Griffiths

Date: 09:37:52 02/14/01

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On February 14, 2001 at 10:11:53, Carmelo Calzerano wrote:

>On February 14, 2001 at 09:35:58, Larry Griffiths wrote:
>
>>Carmelo,
>>
>>I will dink around with the hash table some more and see if I can find a bug
>>somewhere.
>>
>>Is this Fine 70?
>>
>>[D]8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - -
>
>Exactly ;-)
>
>Bye,
>Carmelo

Ok Carmelo,

I did find a bug in my hash code and am getting upper_bound cutoffs now.
I owe you one since I was about to give up on the hash table for a while.
I ran the Fine 70 position using a 16meg hash table.  My hash tables are
28 bytes in size.

My program goes 17 plys in 18 seconds without the hash table,
and 19 plys in 6 seconds with the hash table.

I noticed that Hardly any of the 16meg hash table was used.  I am only using 1
slot per hash key, and maybe if I add/look at the next 8 slots I can get some
more entries in the hash table and go deeper on plys.  I do not know if I will
be able to get 33 plys (impressive).  I found a bug in my hash table code a few
days ago that might explain why my program was making bad moves with my old hash
table code.

Thanks so much for your help.
By the way, what is your chess program name?

Larry.



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