[Beowulf] Random numbers (was Re: /dev/random entropy on stateless/headless nodes)

[Heiko Bauke]

Hi,

On Sun, 27 Feb 2011 11:48:28 -0500 (EST)
"Robert G. Brown" <rgb at phy.duke.edu> wrote:

> The solution for nearly anyone needing large numbers of fast, high
> quality random numbers is going to be:  Use a fast, high quality
> random number generator from e.g. the Gnu Scientific Library, and
> >>seed<< it from /dev/random, ensuring uniqueness of the seed(s)
> >>across the cluster

I agree that for Monte Carlo simulations a fast, high quality (pseudo)
random number generator (PRNG) is more appropriate than /dev/{u}random.
However, seeding a PRNG randomly is imho a missconception. Even though
Monte Carlo algorithms utilize a pseudo random resource the final
result of a Monte Carlo simulation should be deterministic and
reproducible. Therefore, for scientific Monte Carlo applications one
should use a known seed. Parallel Monte Carlo applications may derive
streams of pseudo random numbers from a common base sequence by
splitting and leap frogging, see also
http://arxiv.org/abs/cond-mat/0609584 


	Regards,

	Heiko


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--        Heiko Bauke @ http://www.mpi-hd.mpg.de/personalhomes/bauke