Date: Tue, 04 Feb 2003 15:22:03 +0100 From: Dag-Erling Smorgrav <des@ofug.org> To: "Andrey A. Chernov" <ache@nagual.pp.ru> Cc: David Schultz <dschultz@uclink.Berkeley.EDU>, Kris Kennaway <kris@obsecurity.org>, current@FreeBSD.ORG Subject: Re: rand() is broken Message-ID: <xzpisw0unw4.fsf@flood.ping.uio.no> In-Reply-To: <20030204140806.GA93236@nagual.pp.ru> ("Andrey A. Chernov"'s message of "Tue, 4 Feb 2003 17:08:06 %2B0300") References: <20030203002639.GB44914@HAL9000.homeunix.com> <20030203100002.GA73386@nagual.pp.ru> <20030204054020.GA2447@HAL9000.homeunix.com> <20030204094659.GA87303@nagual.pp.ru> <20030204115237.GA6483@HAL9000.homeunix.com> <xzpfzr4b3pw.fsf@flood.ping.uio.no> <20030204131006.GB92301@nagual.pp.ru> <20030204131748.GA92510@nagual.pp.ru> <20030204132845.GA92674@nagual.pp.ru> <20030204134714.GA92940@nagual.pp.ru> <20030204140806.GA93236@nagual.pp.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
"Andrey A. Chernov" <ache@nagual.pp.ru> writes: > With NSHUFF 100 situation not changed much, so I beleive that stated > problem is common for this type PRNGs, so we gains nothing changing > formulae to Knuth-recommended values. Yes we do. We get a better sequence for any given seed, i.e. we get less correlation between n and x(n) for any given x(0). I don't think it changes much for long sequences, but we get a better distribution for short sequences (including short subsequences of long sequences). As for patterns in the lower bits, we should try with a != 0 and see how that affects the results. I believe the purpose of a in the LCG algorithm is to scramble the lower bits. DES -- Dag-Erling Smorgrav - des@ofug.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?xzpisw0unw4.fsf>