round to even digit (PR#3604)
On Thu, 31 Jul 2003 kbroman@jhsph.edu wrote:
Full_Name: Karl W Broman Version: 1.7.1 OS: Linux Submission from: (NULL) (162.129.44.18) There appears to be a slight problem with round(); for rounding off a 5, it should go to the even digit, but there appear to be some cases where it goes to an odd digit; see below.
I think this may be a case where the number doesn't actually end in 5, it just appears to
round(217.5)
[1] 218
round(21.75*10)
[1] 218
round(2.175*100)
[1] 217
round(0.2175*1000)
[1] 218 since .175 isn't exactly expressible in binary. -thomas Thomas Lumley Assoc. Professor, Biostatistics tlumley@u.washington.edu University of Washington, Seattle