[Rd] Truncation error on simply mean & sum function (PR#12515)

[samaya6501 at yahoo.com.tw]

Full_Name: Tom Wang
Version: 2.6.2
OS: Linux, Windows
Submission from: (NULL) (61.230.6.228)


I've found an instance:

> a <- c(0.187,-0.019,0.074,-0.06,0.221,-0.079,0.12,0.079,-0.281,-0.242)
> sum(a)
[1] -2.428613e-17

The actual sum is 0 but it reports the wrong answer.

Maybe it is due to the computer truncation error.