We commit a similar sin in the help pages, e.g. example(set.seed) ; runif(2) example(set.seed) ; runif(2)
gives you the same random uniforms both times. (Of course it isn't that much of an issue, since you would rarely be running examples before any serious simulations.) You can fairly easily work around that by saving and restoring .Random.seed. I wonder if that isn't also true of the cases using set.seed() for other reasons? -pd > On 30 Oct 2019, at 13:46 , Duncan Murdoch <murdoch.dun...@gmail.com> wrote: > > On 30/10/2019 3:28 a.m., Marvin Wright wrote: >> Hi all, >> I recently found several calls of set.seed() in a CRAN package. These calls >> are in a plot function, which could lead to unexpected behaviour. See >> https://github.com/sammo3182/interplot/issues/33 >> <https://github.com/sammo3182/interplot/issues/33> for a description of the >> problem. >> I checked the CRAN repository policies and could not find anything about >> this. I would have expected a policy against setting fixed seeds somewhere >> in a package. Am I missing something? > > set.seed() writes .Random.seed in the user's global environment, which > violates this policy: > > - Packages should not modify the global environment (user’s workspace). > > However, every call to a random number generator creates or modifies > .Random.seed as well, and most of those are expected and shouldn't be > flagged. And interplot() is documented to do random simulations, so it would > be expected to change the seed: the issue is that given the same inputs it > always changes it to the same thing. I think that would be quite hard for a > test to detect. > > Should it be a policy with no test? Maybe, because I agree with you that > interplot()'s set.seed(324) is bad practice. > > Duncan Murdoch > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
