Author: David Rasmussen
Date: 13:26:10 05/22/01
Go up one level in this thread
On May 22, 2001 at 09:52:11, Gian-Carlo Pascutto wrote: >On May 22, 2001 at 09:43:49, Robert Hyatt wrote: > >>>2) How to generate a 64 bit random number? (I use ran()*ran(). Is it OK?). >> Ran*Ran is not OK, as it will favor the higher bits. >>I would use ran()<<32 + ran myself. > >Just make sure you package your own ran(). The quality of C >libraries one will vary greatly. > >I did a test with 32 bit hashes and MSVC: average hamming distance >of 9.30, whereas my own (which I stole from Crafty, which stole it from...) >got 15.99, which is theoretically optimal I suppose. > I'm almost sure that 15.99 is not optimal. I have my own PRNG in my engine (which I stole from...), and I have chosen a good seedvalue, that gives me _minimum_ hamming distance 16. So the average is at least that, and probably higher than that. And as I've stated earlier, there is a non-linear extended 64-bit BCH code with minimum hamming distance 27, and dimension 10 (to get 1024 vectors) if I remember correctly. Of course this is very exceptional, but it can be done.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.