[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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