Author: Dann Corbit
Date: 23:37:45 11/13/01
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On November 14, 2001 at 02:03:47, Gian-Carlo Pascutto wrote: >On November 13, 2001 at 19:34:44, Dann Corbit wrote: > >>64 bits is generally recognized as a good size for a hash, and 32 bits is >>*definitely* too small. > >I am still eagerly waiting to see someone actually produce >valid proof for this claim. Some programs may have a much bigger problem (e.g. fast searchers). Imagine a program that searches 1M nodes/second. There are plenty that can manage that, on steamy hardware. In 1000 seconds, there are 1 billion nodes, and in 4000 seconds (a bit over an hour) a 32 bit integer has been exhausted. By this time, it is absolutely sure to have collisions. Now, imagine a correspondence player, letting the computer think overnight. Each position will have been randomly overwritten 20 times a day (roughly speaking). I saw a rough mathematical justification somewhere (but I can't remember where it was).
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