You need to heed Rolf's advice. N random integers by definition cannot have a fixed sum.
Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Tue, Jul 10, 2018 at 5:11 PM, Nelly Reduan <nell.r...@hotmail.fr> wrote: > Thank you very much for your reply. > > > By omitting the probability, the expected results could be: > > > c(2, 0, 0, 0, 0, 0, 1, 0, 5, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0) > > > c(0, 0, 1, 0, 0, 1, 1, 0, 6, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0) > > > If I omit the probability, I would like to generate N random positive > integers that sum to M and the integers would be selected from a uniform > distribution. > > > Many thanks for your time > > Nell > > > ________________________________ > De : Rolf Turner <r.tur...@auckland.ac.nz> > Envoyé : mercredi 4 juillet 2018 16:11:11 > À : Nelly Reduan > Cc : r-help@r-project.org > Objet : Re: [R] Generate N random numbers with a given probability and > condition > > > On 05/07/18 10:21, Nelly Reduan wrote: > > > Dear all, > > > > I would like to generate N random numbers with a given probability and > condition but I'm not sure how to do this. > > For example, I have N = 20 and the vector from which to choose is seq(0, > 10, 1). I have tested: > > > > x <- sample(seq(0, 10, 1), 20, replace=TRUE, prob=rep(0.28, > times=length(seq(0, 10, 1)))) > > > > But I don�t know how to put the condition sum(x) <= max(seq(0, 10, 1)). > > Many thanks for your time. > > Your thinking requires considerable clarification. > > (1) Note that seq(0,10,1) is just 0, 1, 2, ..., 10. > > (2) Hence length(seq(0,10,1)) is 11. > > (3) Likewise max(seq(0,10,1)) is 10. > > (4) Your prob vector is *constant* --- so specifying "prob" makes > no difference --- the result is the same as if you omitted "prob". > > (5) You need to think carefully about what you really mean by "random". > In what way do you want the final result to be "random"? > > I expect that the lecturer who assigned this problem to you needs to > clarify his/her thinking as well. > > cheers, > > Rolf Turner > > -- > Technical Editor ANZJS > Department of Statistics > University of Auckland > Phone: +64-9-373-7599 ext. 88276 > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > [[alternative HTML version deleted]] ______________________________________________ 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.
