Prof Brian Ripley wrote: > On Mon, 25 Sep 2006, Gad Abraham wrote: > >> Hi, >> >> It seems to me that the Mersenne-Twister PRNG can be initialised using >> one integer instead of 624 integers, since inside RNG.c code there's a >> function defined as MT_sgenrand(Int32). >> >> How do I actually set this seed within R? > > set.seed(), on the help page for ?.Random.seed. > >> I've tried: >> >> > .Random.seed <- c(3, 1) >> > runif(1) >> Error in runif(1) : .Random.seed has wrong length > >> From the help page > > '.Random.seed' is an integer vector, containing the random number > generator (RNG) *state* for random number generation in R. It can > be saved and restored, but should not be altered by the user.
Ah yes, now I see that .Random.seed is the state, not the actual seed. > >> In addition, is '3' actually the correct rng.kind for the >> Mersenne-Twister? >> >> I'm using R version 2.2.1, 2005-12-20 on Ubuntu Dapper Linux 686. > > Not current, but I suspect the help page is the same in that version. > Thanks for clarifying that, now I can ask my next question: I would like to set the same seed in R and in another implementation of the Mersenne-Twister (MersenneTwister.java by Sean Luke, at http://cs.gmu.edu/~sean/research/mersenne/MersenneTwister.java), in order to get the same set of random deviates. In Java: MersenneTwister mt = new MersenneTwister(1); // set seed System.out.println("result = " + mt.nextDouble()); // result is 0.4170220046815992 In R: > set.seed(1, kind = "Mersenne-Twister") > runif(1) [1] 0.2655087 Why are the random deviates different? Thanks, Gad -- Gad Abraham Department of Mathematics and Statistics University of Melbourne Parkville 3010, Victoria, Australia email: [EMAIL PROTECTED] web: http://www.ms.unimelb.edu.au/~gabraham ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
