Date: Tue, 4 Feb 2003 16:02:38 +0300 From: "Andrey A. Chernov" <ache@nagual.pp.ru> To: Kris Kennaway <kris@obsecurity.org>, current@FreeBSD.ORG Subject: Re: rand() is broken Message-ID: <20030204130238.GA92301@nagual.pp.ru> In-Reply-To: <20030204120730.GA91888@nagual.pp.ru> References: <20030202070644.GA9987@rot13.obsecurity.org> <20030202090422.GA59750@nagual.pp.ru> <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> <20030204120730.GA91888@nagual.pp.ru>
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On Tue, Feb 04, 2003 at 15:07:30 +0300, Andrey A. Chernov wrote: > On Tue, Feb 04, 2003 at 03:52:37 -0800, David Schultz wrote: > > > > You can do better than the present generator with 32 bits of state. > > See the following page by Neal Wagner (not to be confused with David Wagner): > > http://www.cs.utsa.edu/~wagner/laws/rng.html > > The section on LCGs suggests that the multiplier FreeBSD uses (7^5) > > is not particularly good, and points out some better values suggested > > by Knuth. I can't find the original discussion in TAOCP vol. 2, but Two variants looks interesting from that paper: m=2^31-1, k=48271 m=2^31-1, k=62089911 Do you know any comparison of them with what we currently have, i.e. m=2^31-1, k=16807 -- Andrey A. Chernov http://ache.pp.ru/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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