Der Vincent, RNGkind("L'Ecuyer-CMRG") works as using mc.set.seed=FALSE.
When mc.cores changes, the output is not reproducible. I think this issue is also of concern within the Bioconductor community as parallel version of permutation test is commonly used now. Best Regards, Guangchuang On Wed, Jun 3, 2015 at 5:17 PM, Vincent Carey <st...@channing.harvard.edu> wrote: > Hi, this question belongs on R-help, but perhaps > > https://stat.ethz.ch/R-manual/R-devel/library/parallel/html/RngStream.html > > will be useful. > > Best regards > > On Wed, Jun 3, 2015 at 3:11 AM, Yu, Guangchuang <g...@connect.hku.hk> > wrote: > >> Dear all, >> >> I have an issue of setting seed value when using parallel package. >> >> > library("parallel") >> > library("digest") >> > >> > set.seed(0) >> > m <- mclapply(1:10, function(x) sample(1:10), >> + mc.cores=2) >> > digest(m, 'crc32') >> [1] "4827c80c" >> > >> > set.seed(0) >> > m <- mclapply(1:10, function(x) sample(1:10), >> + mc.cores=2) >> > digest(m, 'crc32') >> [1] "e95b9134" >> >> By default, set.seed() will be ignored since mclapply will set the seed >> internally. >> >> If we use mc.set.seed=FALSE to disable this feature. It works as indicated >> below: >> >> > set.seed(0) >> > m <- mclapply(1:10, function(x) sample(1:10), >> + mc.cores=2, mc.set.seed = FALSE) >> > digest(m, 'crc32') >> [1] "6bbada78" >> > >> > set.seed(0) >> > m <- mclapply(1:10, function(x) sample(1:10), >> + mc.cores=2, mc.set.seed = FALSE) >> > digest(m, 'crc32') >> [1] "6bbada78" >> >> The problems is that the results are also depending on the number of >> cores. >> >> > set.seed(0) >> > m <- mclapply(1:10, function(x) sample(1:10), >> + mc.cores=4, mc.set.seed = FALSE) >> > digest(m, 'crc32') >> [1] "a22e0aab" >> >> >> Any idea? >> >> Best Regards, >> Guangchuang >> -- >> --~--~---------~--~----~------------~-------~--~----~ >> Guangchuang Yu, PhD Candidate >> State Key Laboratory of Emerging Infectious Diseases >> School of Public Health >> The University of Hong Kong >> Hong Kong SAR, China >> www: http://ygc.name >> -~----------~----~----~----~------~----~------~--~--- >> >> [[alternative HTML version deleted]] >> >> _______________________________________________ >> Bioc-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/bioc-devel >> > > -- --~--~---------~--~----~------------~-------~--~----~ Guangchuang Yu, PhD Candidate State Key Laboratory of Emerging Infectious Diseases School of Public Health The University of Hong Kong Hong Kong SAR, China www: http://ygc.name -~----------~----~----~----~------~----~------~--~--- [[alternative HTML version deleted]] _______________________________________________ Bioc-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/bioc-devel