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Subject: Re: Hash table question

Author: Larry Griffiths

Date: 06:55:04 02/19/01

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On February 19, 2001 at 06:01:36, Carmelo Calzerano wrote:

>On February 18, 2001 at 11:29:39, Larry Griffiths wrote:
>
>>Hi,
>>
>>I use a reference indicator in my hash entries when the hash key matches.
>>
>>Only 20 to 40% of the hash entries are being referenced during a tree search.
>>
>>Is this a normal range?
>
>
>Surely not, unless the number of entries in the table is much bigger than the
>number of nodes you visit in the search (which is usually not the case).
>
>Hash entry references must be equally distributed; i.e., if you have a 1 M
>entries in your hash and search 100 M nodes, you should find each hash entry
>referred about 100 times (with small statistical fluctuations of course).
>
>HTH
>
>Bye,
>Carmelo

I used Bob's Random64() function to produce the Hash keys.  I also created two
hash tables so that black and white positions would not overlay each other.
I even use slots and will do a hash add within the next 7 slots if the primary
hash slot add fails.

It may be that positions that caused cutoffs are never seen again because
succeeding cutoffs occur.

Larry.



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