Could very easily be chipset, but I'm actually running a Pentium 4 myself. Pentium 4 1.9GHz, on a Windows XP Professional Version 2002 Service Professional, Service Pack 1.
Also of interest, > 1 %% 0.2 [1] 0.2 > 1 %% 0.25 [1] 0 -----Original Message----- From: Prof Brian Ripley [mailto:[EMAIL PROTECTED] Sent: Thursday, May 12, 2005 3:39 AM To: r-devel@stat.math.ethz.ch Subject: RE: [Rd] bug in modulus operator %% (PR#7852) I've now found a Windows system that does this. This is also Windows XP, fully patched, and with the same rw2010. So it may be chip-specific: the one that works is a P4 and the one that does not is a latest Pentium M. I am not sure that the guarantee on the help page has been supported for a while. I've altered the code so it is more likely to be. BTW, > options(digits=20) > 1 %% 0.001 [1] 0.0009999999999999792 shows why the original is not a bug in R. On Thu, 12 May 2005 [EMAIL PROTECTED] wrote: > On Wed, 11 May 2005 [EMAIL PROTECTED] wrote: > >> Yes, you are correct. I had only checked one of my platforms. Linux >> works as you suggest. But for me on Windows, >> >>> x <- 1 >>> y <- 0.2 >>> x %/% y >> [1] 5 ## I get a 4 in Linux > > I get 5 on Windows, but > >> (x %% y) + y * (x %/% y) > [1] 1 > > so is there a problem particular to your Windows runtime? > > >> >> version >> _ =20 >> platform i386-pc-mingw32 >> arch i386 =20 >> os mingw32 =20 >> system i386, mingw32 =20 >> status =20 >> major 2 =20 >> minor 1.0 =20 >> year 2005 =20 >> month 04 =20 >> day 18 =20 >> language R =20 >> >> >> -----Original Message----- >> From: Peter Dalgaard [mailto:[EMAIL PROTECTED] >> Sent: Wednesday, May 11, 2005 4:14 PM >> To: McGehee, Robert >> Cc: [EMAIL PROTECTED]; Peter Dalgaard; [EMAIL PROTECTED]; >> [EMAIL PROTECTED]; r-devel@stat.math.ethz.ch >> Subject: Re: [Rd] bug in modulus operator %% (PR#7852) >> >> >> "McGehee, Robert" <[EMAIL PROTECTED]> writes: >> >>> Yes, but from ?"%%": >>> "It is guaranteed that 'x =3D=3D (x %% y) + y * (x %/% y)' (up to = >> rounding >>> error) ..." >>> =20 >>> (R 2.1.0) >>>> x <- 1 >>>> y <- 0.2 >>>> x %% y >>> [1] 0.2 >>>> (x %% y) + y * (x %/% y) >>> [1] 1.2 >>> =20 >>> Certainly 1 does not equal 1.2 as the documentation would suggest, and >>> these seem like large enough numbers to not be effected by rounding >>> errors or lack of precision. >> >> Now that looks a bit odd, but it isn't universal: >> >>> x <- 1 >>> y <- 0.2 >>> x %% y >> [1] 0.2 >>> x %/% y >> [1] 4 >>> (x %% y) + y * (x %/% y) >> [1] 1 >> >> So what platform was that happening on? -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-devel@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
