Google for "round to even", and read the Details section of ?round.
On 11 Apr 2014, at 10:42 , Per Nielsen <evil...@gmail.com> wrote: > Hi all > > I have encountered some strange/wrong behavior of the round function in R. > > This is the behavior on my mac laptop: > >> R.version > _ > platform x86_64-apple-darwin13.0.2 > arch x86_64 > os darwin13.0.2 > system x86_64, darwin13.0.2 > status > major 3 > minor 0.2 > year 2013 > month 09 > day 25 > svn rev 63987 > language R > version.string R version 3.0.2 (2013-09-25) > nickname Frisbee Sailing >> round(1.5) > [1] 2 >> round(4.5) > [1] 4 >> floor(1.5 + 0.5) > [1] 2 >> floor(4.5 + 0.5) > [1] 5 > > This is the behavior on Ubuntu 12.04 running in a virtual machine on the > same mac: > >> R.version > _ > platform x86_64-pc-linux-gnu > arch x86_64 > os linux-gnu > system x86_64, linux-gnu > status beta > major 3 > minor 1.0 > year 2014 > month 03 > day 28 > svn rev 65330 > language R > version.string R version 3.1.0 beta (2014-03-28 r65330) > nickname Spring Dance >> round(1.5) > [1] 2 >> round(4.5) > [1] 4 >> floor(1.5 + 0.5) > [1] 2 >> floor(4.5 + 0.5) > [1] 5 > > I would expect round(x.5) = x+1, which only happens sometimes. My colleague > using R version 3.1.0 on Linux on a Lenovo laptop gets the expected result > in all cases. > > Is this a bug or somehow expected behavior? It seems to be related to the > mac hardware. I can ad hoc fix it using floor, but that is hardly optimal. > > Thanks, > Per > > [[alternative HTML version deleted]] > > _______________________________________________ > R-SIG-Mac mailing list > R-SIG-Mac@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-mac -- Peter Dalgaard, Professor Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com _______________________________________________ R-SIG-Mac mailing list R-SIG-Mac@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-mac
