R-alpha: compatibility
This is one point where compatibility is not necessarily a good thing. S, like most systems gives, you no real control over the random number generator expect re-seeding. Usually this is probably good. But most simulation books recommend running any simulations you care about with two very different generators. Most people don't do this because one generator is usually easy to use (the built-in one in your favorite system) and anything else is impossible. Another issue that S faces has to do with running separate bits of a simulation on separate workstations. Unless you are careful, the separate bits will share parts of random number streams, and being careful is not really possible with S's generator (I think) -- it is possible but not easy with R's. (Of course overlap can be a good thing if you know you have it -- the point here is that lots of folks run separate simulations thinking they have independent runs when they probably do not in any reasonable sense). The bottom line is that it would be nice to eventually provide "power users" with more control over the random number generator system. Now is clearly not the time to think about how to do that, but it would be unfortunate if decisions were made at this point in the name of compatibility that might limit the freedom of doing something "right" later on. Just my 2c. luke
Luke Tierney University of Minnesota Phone: 612-625-7843 School of Statistics Fax: 612-624-8868 206 Church Street email: luke@stat.umn.edu Minneapolis, MN 55455 USA WWW: http://www.stat.umn.edu =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-