R help - Sep 2006 - Initialising Mersenne-Twister with one integer

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?

I've tried:

 > .Random.seed <- c(3, 1)
 > runif(1)
Error in runif(1) : .Random.seed has wrong length

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.

Thanks,
Gad

-- 
Gad Abraham
Department of Mathematics and Statistics
University of Melbourne
Parkville 3010, Victoria, Australia
email: g.abraham at ms.unimelb.edu.au
web: http://www.ms.unimelb.edu.au/~gabraham

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.
> 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.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595