[Rd] set.seed and /dev/random
saptarshi.guha at gmail.com
Sun May 3 16:54:58 CEST 2009
On Sat, May 2, 2009 at 7:21 PM, Dirk Eddelbuettel <edd at debian.org> wrote:
> On 2 May 2009 at 18:53, Saptarshi Guha wrote:
> | Hello,
> | In ?set.seed I notice that a seed is created from the system time.
> | Thus if two machines were (hypothetically) running for the same time
> | and R was started simultaneously on both, the would have the same
> | seeds (correct?).
> | I assume reading from /dev/random would be different for both of these
> | machines, so my question is why not use an integer read from
> | /dev/random to create the seed?
> Some folks do. But do read the fine print about entropy etc.
> An alternnative is provided by the random package on CRAN (slightly
> re-indented below).
> R> library(help=random)
> Information on package 'random'
> Package: random
> Version: 0.2.0
> Date: $Date: 2009-01-03 11:45:17 -0600 (Sat, 03 Jan 2009) $
> Author: Dirk Eddelbuettel <edd at debian.org>
> Maintainer: Dirk Eddelbuettel <edd at debian.org>
> Title: True random numbers using random.org
> Description: This package provides an interface to the true random number
> service provided by the random.org website created by Mads
> Haahr. The random.org web service samples atmospheric noise
> via radio tuned to an unused broadcasting frequency together
> with a skew correction algorithm due to John von Neumann.
> More background is available in the included vignette based on
> an essay by Mads Haahr. In its current form, the package
> offers functions to retrieve random integers, randomized
> sequences and random strings.
> Depends: R (>= 2.8.0)
> License: GPL Version 2
> URL: http://www.random.org
> Built: R 2.8.1; ; 2009-01-03 11:46:25; unix
> random True random numbers from random.org
> Further information is available in the following vignettes in directory
> random-essay: random.org: Introduction to Randomness and Random Numbers (source, pdf)
> random-intro: random: An R package for true random numbers (source, pdf)
> | Would it be a portability issue?
> | I must admit I have very little idea about RNGs, so my question is
> | possibly very naive.
> | Thank you
> | Saptarshi
> | ______________________________________________
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> Three out of two people have difficulties with fractions.
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