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Subject: Re: About debugging HashTables implementation .

Author: Pat King

Date: 08:56:45 04/09/02

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On April 08, 2002 at 15:17:46, Robert Hyatt wrote:

>On April 08, 2002 at 12:38:35, John Marountas wrote:
[snip]
>>When searching into the HashTable I keep a record of the returned
>>Lows,Highs and Hash Collisions. Here are the results:
>>
>>Hash Collisions: 1000
>>Hash High      :  173
>>Hash Low       :    0
>>
>>Best Move : 3...Nxd4
>>
>>Why there are  so many collisions?
>
>
>How do you define "collision"?  Normally this means two different board
>positions produce the same hash signature.  If you are getting _those_ you
>have a Zobrist hashing bug.

How do you detect collisions, then? Record the entire position in the hash
table? Even for a debug build, that seems like it would be impractical. Although
undetected hash bugs are even less practical :)

>If you mean two different signatures hash to the
>same board position then perhaps your 64 bit random numbers are very poorly]
>chosen...
[snip]



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