Author: Tom Likens
Date: 19:39:35 07/11/03
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On July 11, 2003 at 18:06:56, Ricardo Gibert wrote: >On July 11, 2003 at 17:50:21, Ricardo Gibert wrote: > >>On July 11, 2003 at 17:23:10, Tom Likens wrote: >> >>[snip] >> >>>I probably haven't solved your problem but of course these things >>>are insidious. Also I could easily be misinterpreting some of >>>your code, if so I apologize. >>> >>>Some general advice, you probably should convert to 64-bit hash >>>keys to reduce the chance of collisions. >> >> >>Actually, every program should allow this to be configurable. For instance, an >>8-bit hash can be useful in debugging and a 32-bit hash is something interesting >>and not known for certain to be a bad idea. This is a valid point. It's intriguing that even though a 32-bit hash key *will* result in collisions, the real question is wheter those collisions will actually propagate back up the tree and cause the program to select an inferior move. >Just want to add that a 256-bit hash key can be useful for debugging too. By >contrasting 64-bit with 256-bit, one might conclude that the quality of the >random numbers is wanting. I'm not sure I follow this. I'm guessing (without actually testing it) that the difference in the number of collisions between a 64-bit hash key and a 256-bit hash key would be vanishingly small for the typical search trees that modern programs explore. Is there some other advantage of a 256-bit hash key over a 64-bit key that I'm missing? regards, --tom
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