[R] Bug in rep() function

[Samuel Knapp]

Dear all,

I have discovered a bug in the standard rep() function: At certain 
values, rep() does not replicate the element by the proper number of times:

 > a <- (1-0.9)*100
 > a
[1] 10
 > length(rep(1,times=a))
[1] 9
 > length(rep(1,each=a))
[1] 9

As shown, this happens as well for the times= as for the each= 
parameter. It does not depend on the kind of element that is to be repeated:

 > length(rep("abc",each=a))
[1] 9

I tried to narrow down the bug, but haven't really managed to find a 
pattern behind the bug. Here is a list with values for a (see above) 
that returns a false object ( after the value for a, i've collected the 
expected length and the length that is produced by r):

# mistake at
(1-0.9)*100       10           9
(1-0.8)*100       20          19
(1-0.8)*1000      200       199
(1-0.9)*1000      100       99
(1-0.9)*10            1         0
(1-0.8)*10            2         1
(1-0.9)*1000000000      100000000       99999999
(2-1-0.9)*100         10      9
(10/10-0.9)*100     10      9

# the following sets for a work fine
(1+0.1)*100
(1-0.1)*100
(1-0.7)*100
(1-0.99)*1000
(1-0.7)*10
(1-0.90)*10
(1-0.95)*100
(1-0.95)*1000
(2-0.9)*1000
(2-1.9)*100
(1.1-1)*100
(10-9)*100

Did I make any mistake? Or where else should I address this problem?

Thanks and best regards,
Samuel