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Subject: Re: 64-Bit random numbers

Author: Dieter Buerssner

Date: 13:27:18 10/30/03

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You might also enjoy to read http://www.chess-archive.com/ccc.php?art_id=190318
which shows some experiment about collisions, and that they are really not worth
to mention as a practical problem in typical situations. I just tested "Gerd's"
PRNG (close to the start of this thread). I is really bad as a PRNG. For
example, a simple test that tries to find out how many lower case letter that
PRNG will find. When we assume that 'a' is 0, 'b' 1, etc. and we take the lower
8 bits of that PRNG. One would assume, (26 letters - 256 possibilities for lower
8 bits), that one would find one word in 1000 calls to the PRNG. But that PRNG
is really bad - it won't find even one word after letting it run for years (That
PRNG will never output 3 numbers in a row, where the last 8 bits are < 26).
Still - it will work nicely for "our" Zorbrist type hashing.

Regards,
Dieter



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