Date: Mon, 17 Feb 2003 14:47:59 +0300 From: "Andrey A. Chernov" <ache@nagual.pp.ru> To: Tim Robbins <tjr@FreeBSD.ORG> Cc: Kris Kennaway <kris@obsecurity.org>, current@FreeBSD.ORG Subject: Re: cvs commit: src/lib/libc/stdlib rand.c Message-ID: <20030217114759.GA31054@nagual.pp.ru> In-Reply-To: <20030217173955.A29826@dilbert.robbins.dropbear.id.au> References: <200302170352.h1H3qawJ062671@repoman.freebsd.org> <20030217045729.GA68471@rot13.obsecurity.org> <20030217164048.A28273@dilbert.robbins.dropbear.id.au> <20030217055309.GA28024@nagual.pp.ru> <20030217173955.A29826@dilbert.robbins.dropbear.id.au>
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On Mon, Feb 17, 2003 at 17:39:55 +1100, Tim Robbins wrote: > > variant (which generates bad quality ones), the only problem remains is > > first value monotonically increased with the seed. > > Here's an interesting picture of that: http://people.freebsd.org/~tjr/rand.gif > Nothing surprising here. It is common and know problem for all mod-type PRNGs. There is even good methods exists to eliminate this thing, see http://www.physik.uni-giessen.de:8081/PhysOfFinance/PoF09.pdf "Shuffling Algorithm" section for example. But all such methods will be incompatible with rand_r()... -- 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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