Author: Robert Hyatt
Date: 07:13:20 09/17/00
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On September 17, 2000 at 02:46:34, Larry Griffiths wrote: >On September 16, 2000 at 23:54:19, Robert Hyatt wrote: > >> >>what random() function are you using? IE stock random() doesn't have any >>arguments. If it is a seed, there are known good and bad seeds. In almost >>_all_ cases, you want the seed to be odd, and usually prime. > >I tried using my compilers rand() function but it was only generating >random numbers from 0 to 0x7fff. > >I ran 78 positions from the BWTC suite >and got over 10,000 mis-matches using my 64-bit hash keys. >I looked at my smallboards and they usually differ by a piece missing or in a >different position. My Piece table does not have zero or duplicate entries >and the random numbers in the piece table look good. >I built hashkeys using the two different smallboards and they do indeed >generate the same hashkeys. > >Maybe my hashkeys should be prime numbers? > >I will play around with random some more and see if it changes my mismatch >rate. > >Thanks Bob. > >Larry. You want numbers with about 1/2 the bits on, 1/2 off. And then you want the 'hamming distance' between any two numbers to be maximized (64 bits would be nice but is only possible for two numbers, not a larger set).
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