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Subject: Re: Hashkey collisions (typical numbers)

Author: James Swafford

Date: 05:56:26 04/07/04

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On April 07, 2004 at 06:55:31, Andrew Williams wrote:

>On April 07, 2004 at 06:49:59, Renze Steenhuisen wrote:
>
>>
>>Hi all,
>>
>>could someone give me some numbers that are common with hashkey collisions?
>>Because I guess my % is little too high...
>>
>>I'm getting like 0.03% [which is 1 every 3000, if I'm not mistaken]
>>
>>This is when using TT=32MB (haven't got the exact number of entries)
>>
>>If you think it is an error, any suggestions on where to start looking?
>>
>>Thanks!
>>
>>   Renze
>
>One in 3000 seems very high. How many bits are there in your hashkey?
>
>Andrew


Even though you said you're using Crafty's random num gen,
I would start by doing some hamming-distance checks.

For reference, my program gets:
Checking minimum hamming distance between random keys: 14 bits
Checking average hamming distance between random keys: 31 bits

If your hamming distances are comparable, you can conclude
your zobrist keys are ok, and go from there.

--
James



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