Hi Jay & Matthias That's exactly what I was looking for.
Thanks a lot Rainer G. Jay Kerns wrote: > 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. >> > > ______________________________________________ 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.
