[R] analytical solution to Sum of binominal distributed random numbers?

[Rainer M. Krug]

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:  FredeA.Togersen at agrsci.dk
> 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: r-help-bounces at r-project.org 
>> [mailto:r-help-bounces at r-project.org] 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 at 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:cberry at tajo.ucsd.edu	            UC San Diego
>>> http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 
>>> 92093-0901
>>>
>>> ______________________________________________
>>> R-help at 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 at 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.
>>