[R] simple questions about R

Prof Brian Ripley ripley at stats.ox.ac.uk
Wed Nov 4 20:50:50 CET 1998

> From: Francisco Cribari <cribari at de.ufpe.br>
> A few simple questions from a novice R user. (I am running
> R version 0.62.3 Beta (Sept 8, 1998) under Windows NT.)
> 2) Can anyone send me details on the random number generator
>    used by R (period, etc.). Also, why is it different from
>    the SuperDuper RNG in S?

That is rather well-documented: see help(.Random.seed).  It is the sum
modulo 1 of three rather poor multiplicative congruential generators.

I think exactly copying S (or S-PLUS: there are some differences)
would be subject to complaints of copyright infringement. 

> 3) Will there be an  l1fit  function in future releases
>    of R?

None is planned. You can use my rlm function (in library MASS;
better versions to come) to do this slowly: take k to be very small
in the Huber M-estimator. However, I see no statistical advantages
in the L1 regression over the alternatives already available for
R (under Unix, at least).

If you see a need for one, please write it and submit it. It will
need to be in compiled code to be useful, I think.

Until we can resolve the problems with dynamic loading, package
availability for Windows is going to be rather limited. (At present
it works on some systems but not others: in particular, not on mine.)

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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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