[R] problem with function "rep"

[Erik Iverson]

Berwin appears to be correct here.  After you do x <- x / 0.0001,
I inserted a call to round(x) - x, and received

round(x) - x
[1] 7.275958e-12 0.000000e+00 0.000000e+00

This is basically a case of FAQ 7.31.


Julien Hunt wrote:
> Hi I believe this should provide an example of the confusing behavior.
> 
> Run this with t=100 for example:
> 
> test=function(t){
> 
> x=c()
> while(sum(x)<=t){
> ###I simply generate some numbers from an exponential until the sum of 
> these numbers gets to 100(without loss of generality)
> x=c(x,round(rexp(1,0.1),4))
> }
> x=x/0.0001
> 
> y=rnorm(length(x),0,1)
> t=rep(y,x)
> 
> return(sum(x),length(t))
> 
> }
> 
> The intuition is that sum(x) and length(t) should be the same. 
> furthermore, rounding x seems since all is done for it to be an integer. 
> Nevertheless, I will try Berwin Turlach's method.
> Regards,
> Julien
> 
> At 17:01 12/06/2008, Erik Iverson wrote:
>> We need a reproducible example of this to tell you what is going on. 
>> Find a small example that exhibits the confusing behavior, and share 
>> it with the list.
>>
>> Julien Hunt wrote:
>>> To whom it may concern,
>>> I am currently writing a program where I need to use function rep.
>>> The results I get are quite confusing. Given two vectors A and B, I 
>>> want to replicate a[1] b[1] times, a[2] b[2] times and so on.
>>> All the entries of vector B are positive integers.
>>> My problem comes from the fact that if I sum up all the elements of 
>>> B, I get a certain value  x(for example 10000). And if i calculate 
>>> the length of the vector obtained after replication, I dont always 
>>> get x(10000) but sometimes I get x sometimes I get 9999 instead of 10000.
>>> Has this problem been reported before? Do you need more information 
>>> on my specific program.
>>> Thanks for your time and help,
>>> Best regards,
>>> Julien Hunt
>>> Julien Hunt,
>>> PhD student and teaching assistant,
>>> Institute of Statistics,
>>> Université Catholique de Louvain,
>>> Voie du Roman pays 20
>>> B-1348 Louvain-La-Neuve,
>>> Belgium
>>> E-mail: Julien.Hunt at uclouvain.be
>>> Tel: +32 10 / 47 94 01
>>> *****************************************************
>>>
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>>>
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>>
>> Julien Hunt,
>> PhD student and teaching assistant,
>> Institute of Statistics,
>> Université Catholique de Louvain,
>> Voie du Roman pays 20
>> B-1348 Louvain-La-Neuve,
>> Belgium
>>
>> E-mail: Julien.Hunt at uclouvain.be
>> Tel: +32 10 / 47 94 01
>> *****************************************************
>>