Dear R-help mailing list,
First of all, many many thanks for your great work on the R project! I have a very small issue regarding the sample function. Depending if we specify values for the prob argument, we don't get the same result for a random sampling with replacement and with equal probabilities. See the attached R code for a minimal example with the R version 3.6.0. With a previous R version (3.5.x), the result was just a permutation between the possible realizations. They are now totally different with the latest R version. I understand that if we specify or not the prob argument, two different internal functions are used: .Internal(sample()) or .Internal(sample2()). Indeed, the algorithm used to draw a sample may not be the same if by default we assume equal probabilities (without the prob argument) or if the user defines himself the probabilities (even if they are equal). I found this post on stackoverflow which explains the reasons of this difference (answer by Matthew Lundberg): https://stackoverflow.com/questions/23316729/r-sample-probabilities-defaul t-is-equal-weight-why-does-specifying-equal-weigh I was wondering whether the solution proposed by PatrickT could solve this issue? He proposed to have something like if(all.equal(prob, prob, tolerance = .Machine$double.eps) prob = NULL inside the sample.int routine in order to replicate prob=NULL with prob=rep(1, length(x)). Thanks you in advance for your response. Best regards, Ronan Le Gleut Helmholtz Zentrum Muenchen Deutsches Forschungszentrum fuer Gesundheit und Umwelt (GmbH) Ingolstaedter Landstr. 1 85764 Neuherberg www.helmholtz-muenchen.de Stellv. Aufsichtsratsvorsitzender: MinDirig. Dr. Manfred Wolter Geschaeftsfuehrung: Prof. Dr. med. Dr. h.c. Matthias Tschoep, Heinrich Bassler, Kerstin Guenther Registergericht: Amtsgericht Muenchen HRB 6466 USt-IdNr: DE 129521671 ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
