Hi Rainer, The distr package can calculate the distribution for you:
library(distr) X <- Binom(size = 7, prob = 0.3) Y <- Binom(size = 11, prob = 0.5) Z <- X + Y d(Z)( 0:18 ) # the pmf r(Z)( n = 5 ) # random variates Please note, however, that size and prob must be of length 1. Best, Jay On 10/24/07, Rainer M. Krug <[EMAIL PROTECTED]> wrote: > Frede Aakmann Tøgersen wrote: > > Perhaps > > > > http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=ADA266969&Location=U2&doc=GetTRDoc.pdf > > > > is something that you can use? > > Thanks a lot - that might help. > > Rainer > > > > > > > > > Best regards > > > > Frede Aakmann Tøgersen > > Scientist > > > > > > UNIVERSITY OF AARHUS > > Faculty of Agricultural Sciences > > Dept. of Genetics and Biotechnology > > Blichers Allé 20, P.O. BOX 50 > > DK-8830 Tjele > > > > Phone: +45 8999 1900 > > Direct: +45 8999 1878 > > > > E-mail: [EMAIL PROTECTED] > > Web: http://www.agrsci.org > > > > This email may contain information that is confidential. > > Any use or publication of this email without written permission from > > Faculty of Agricultural Sciences is not allowed. > > If you are not the intended recipient, please notify Faculty of > > Agricultural Sciences immediately and delete this email. > > > > > > > > > > > >> -----Oprindelig meddelelse----- > >> Fra: [EMAIL PROTECTED] > >> [mailto:[EMAIL PROTECTED] På vegne af Rainer M Krug > >> Sendt: 24. oktober 2007 09:11 > >> Til: Charles C. Berry > >> Cc: r-help > >> Emne: Re: [R] analytical solution to Sum of binominal > >> distributed random numbers? > >> > >> Hi Charles > >> > >> thanks for the pointing out that size and prob can be vectors > >> as well - I tried it out but used 1 as the number of > >> observations, assuming that and it only gave me one randon > >> mumbewr (as it should be but not expected). > >> > >> But I was more looking at a analytical solution, as I have to > >> sum up a huge number of random numbers. But I am going to try > >> your solution as it should be much faster already. > >> > >> Thanks > >> > >> Rainer > >> > >> > >> Charles C. Berry wrote: > >>> ?rbinom > >>> > >>> only says: > >>> > >>> size: number of trials (zero or more). > >>> > >>> prob: probability of success on each trial. > >>> > >>> > >>> But they can be vectors. > >>> > >>> BTW, you were aked to "PLEASE ... provide minimal, self-contained, > >>> reproducible code." > >>> > >>> What you show cannot run without correction. > >>> > >>> Most likely, you intended size(n) to be the n-th element of > >> the vector > >>> 'size', which in R is written 'size[ n ]' . > >>> > >>> In which case > >>> > >>> sum (rbinom( length(prob) , size, prob ) ) > >>> > >>> works. > >>> > >>> Chuck > >>> > >>> On Tue, 23 Oct 2007, Rainer M Krug wrote: > >>> > >>>> Hi > >>>> > >>>> I have two vectors, prob and size, and I want to add the random > >>>> deviates of these two, i.e. > >>>> > >>>> sum( > >>>> sapply( > >>>> 1:length(prob), > >>>> function(n){ rbinom(1, size(n), prob(n) } > >>>> ) > >>>> ) > >>>> > >>>> My problem is that I have to do this for a large number of value > >>>> combinations. Is there a faster way of doing this? > >>>> > >>>> Rainer > >>>> > >>>> ______________________________________________ > >>>> R-help@r-project.org mailing list > >>>> 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. > >>>> > >>> Charles C. Berry (858) 534-2098 > >>> Dept of > >> Family/Preventive Medicine > >>> E mailto:[EMAIL PROTECTED] UC San Diego > >>> http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego > >>> 92093-0901 > >>> > >>> ______________________________________________ > >>> R-help@r-project.org mailing list > >>> 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. > >> ______________________________________________ > >> R-help@r-project.org mailing list > >> 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. > >> > > ______________________________________________ > R-help@r-project.org mailing list > 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. > -- *************************************************** G. Jay Kerns, Ph.D. Assistant Professor / Statistics Coordinator Department of Mathematics & Statistics Youngstown State University Youngstown, OH 44555-0002 USA Office: 1035 Cushwa Hall Phone: (330) 941-3310 Office (voice mail) -3302 Department -3170 FAX E-mail: [EMAIL PROTECTED] http://www.cc.ysu.edu/~gjkerns/ ______________________________________________ R-help@r-project.org mailing list 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.
