On Fri, 1 Sep 2006, Prof Brian Ripley wrote: > This really is not a good time for us (and apparently you've know about > this for a year). Could you come back to it once 2.4.0 is released (due > Oct 23)?
Oops, a backspace failed: Oct 3. > > [We are busy with getting R-devel ready for 2.4.0, and I think that other > mechanisms for this have been mooted, again at a time which was not > opportune.] > > On Thu, 31 Aug 2006, Josef Leydold wrote: > > > Hi, > > > > As you probably know, there is a problem with the interface for adding > > uniform > > random number generators in R (see by article in R News 5/2, November 2005). > > There exists a mechanism called "user-supplied" that allows users of R > > to run their own generator in R. However, there is no such mechanism for > > package writers. Those who want to add their own generators abuse > > RNGkind(kind="user-supplied") for their purpose. > > The problem with this approach is that it relies on the unique existence of > > the > > function "user_unif_rand". When two packages are loaded that use this > > interface, > > then at least one package is broken. If the user herself loads a shared > > library > > that contains such a function, some of the functionalities of all the > > corresponding packages are broken. > > > > When writing my paper I found the following packages on CRAN that abuse this > > interface (meanwhile there might be more packages): > > > > randaes_0.1.tar.gz > > rlecuyer_0.1.tar.gz > > rsprng_0.3-1.tar.gz > > rstream_1.1.tar.gz > > SuppDists_1.0-13.tar.gz > > > > what makes the situation even more complicated is the fact that some of > > these > > packages are loaded automaticall by other packages. > > For example, package 'rlecuyer' is loaded by > > > > snow_0.2-1.tar.gz > > snowFT_0.0-1.tar.gz > > varSelRF_0.6-2.tar.gz > > > > To solve this problem, Stefan Theussl and I have tried to extend the > > mechanism > > for random number generators in the following way: > > > > - we have added a new kind of generators: "package-supplied" > > > > - this generator kind needs functions named 'package_unif_rand', > > 'package_unif_init', > > 'package_unif_nseed', and 'package_unif_seedloc' > > (analogously to the functions for kind "user-supplied") > > > > - RNGkind has an additional optional argument: > > RNGkind <- function(kind = NULL, normal.kind = NULL, PACKAGE = "") > > argument 'PACKAGE' is only used for the new generator kind > > "package-supplied" > > > > - similarly the function set.seed needs the optinal argument 'PACKAGE' > > > > Since I need such an extended interface (and I assume that other package > > write do also) I ask whether this extension can be included into R. > > We have implemented a first experimental version of this modified > > interface. > > A patch against the development snapshot R-devel_2006-08-30.tar.gz is > > available. > > However, it is a little bit too long (239 lines) to be posted here. > > > > Of course suggestions for an alternative approach are welcome. > > > > Josef > > > > > > > > -- Brian D. Ripley, [EMAIL PROTECTED] 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 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
