Hi, Round(0.55,1)=0.5 Round(2.55,1)=2.6 Can this be right? Thanks, Ed [[alternative HTML version deleted]]
On 11/07/2008, at 8:07 AM, Korn, Ed (NIH/NCI) [E] wrote:> Hi, > > Round(0.55,1)=0.5 > > Round(2.55,1)=2.6 > > Can this be right?Yes. Rolf Turner ###################################################################### Attention:\ This e-mail message is privileged and confid...{{dropped:9}}
I got> round(0.55,1)[1] 0.6> round(2.55,1)[1] 2.5 Your answers are also correct. Please check ?round Quoting "Korn, Ed (NIH/NCI) [E]" <korne at ctep.nci.nih.gov>:> Hi, > > Round(0.55,1)=0.5 > > Round(2.55,1)=2.6 > > Can this be right? > > Thanks, > > Ed > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >
The problem is that neither 0.55 nor 2.55 are exact machine numbers (the computer uses binary representation), so it may happen that the machine representation of 0.55 is slightly less than 0.55 while the machine representation of 2.55 is slightly above 2.55. --- On Fri, 11/7/08, Korn, Ed (NIH/NCI) [E] <korne at ctep.nci.nih.gov> wrote:> From: Korn, Ed (NIH/NCI) [E] <korne at ctep.nci.nih.gov> > Subject: [R] rounding > To: r-help at stat.math.ethz.ch > Received: Friday, 11 July, 2008, 6:07 AM > Hi, > > Round(0.55,1)=0.5 > > Round(2.55,1)=2.6 > > Can this be right? > > Thanks, > > Ed > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, > reproducible code.
Actually, your result is strange, since if x = 0.55 then a hexadecimal representation of x*100 is 404B8000 00000001 which is above 55, meaning that x is above 0.55 and should have been rounded to 0.6, while if x = 2.55 then the hexadecimal representation of x*100 is 406FDFFF FFFFFFFF which is below 255, so that x is less than 2.55 and should have been rounded to 2.5. --- On Fri, 11/7/08, Moshe Olshansky <m_olshansky at yahoo.com> wrote:> From: Moshe Olshansky <m_olshansky at yahoo.com> > Subject: Re: [R] rounding > To: r-help at stat.math.ethz.ch, "Korn, Ed (NIH/NCI) [E]" <korne at ctep.nci.nih.gov> > Received: Friday, 11 July, 2008, 10:39 AM > The problem is that neither 0.55 nor 2.55 are exact machine > numbers (the computer uses binary representation), so it > may happen that the machine representation of 0.55 is > slightly less than 0.55 while the machine representation of > 2.55 is slightly above 2.55. > > > --- On Fri, 11/7/08, Korn, Ed (NIH/NCI) [E] > <korne at ctep.nci.nih.gov> wrote: > > > From: Korn, Ed (NIH/NCI) [E] > <korne at ctep.nci.nih.gov> > > Subject: [R] rounding > > To: r-help at stat.math.ethz.ch > > Received: Friday, 11 July, 2008, 6:07 AM > > Hi, > > > > Round(0.55,1)=0.5 > > > > Round(2.55,1)=2.6 > > > > Can this be right? > > > > Thanks, > > > > Ed > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help at r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide > > http://www.R-project.org/posting-guide.html > > and provide commented, minimal, self-contained, > > reproducible code. > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, > reproducible code.
Here is what I get on a Windows with r2.71> x <- 0.55 > 100*x - 55[1] 7.105427e-15> y <- 2.55 > 100*y - 255[1] -2.842171e-14> round(x,1)[1] 0.6> round(y,1)[1] 2.5>On Thu, Jul 10, 2008 at 9:10 PM, Moshe Olshansky <m_olshansky at yahoo.com> wrote:> Actually, your result is strange, since if x = 0.55 then a hexadecimal representation of x*100 is 404B8000 00000001 which is above 55, meaning that x is above 0.55 and should have been rounded to 0.6, while if x = 2.55 then the hexadecimal representation of x*100 is 406FDFFF FFFFFFFF which is below 255, so that x is less than 2.55 and should have been rounded to 2.5. > > > --- On Fri, 11/7/08, Moshe Olshansky <m_olshansky at yahoo.com> wrote: > >> From: Moshe Olshansky <m_olshansky at yahoo.com> >> Subject: Re: [R] rounding >> To: r-help at stat.math.ethz.ch, "Korn, Ed (NIH/NCI) [E]" <korne at ctep.nci.nih.gov> >> Received: Friday, 11 July, 2008, 10:39 AM >> The problem is that neither 0.55 nor 2.55 are exact machine >> numbers (the computer uses binary representation), so it >> may happen that the machine representation of 0.55 is >> slightly less than 0.55 while the machine representation of >> 2.55 is slightly above 2.55. >> >> >> --- On Fri, 11/7/08, Korn, Ed (NIH/NCI) [E] >> <korne at ctep.nci.nih.gov> wrote: >> >> > From: Korn, Ed (NIH/NCI) [E] >> <korne at ctep.nci.nih.gov> >> > Subject: [R] rounding >> > To: r-help at stat.math.ethz.ch >> > Received: Friday, 11 July, 2008, 6:07 AM >> > Hi, >> > >> > Round(0.55,1)=0.5 >> > >> > Round(2.55,1)=2.6 >> > >> > Can this be right? >> > >> > Thanks, >> > >> > Ed >> > >> > [[alternative HTML version deleted]] >> > >> > ______________________________________________ >> > R-help at r-project.org mailing list >> > https://stat.ethz.ch/mailman/listinfo/r-help >> > PLEASE do read the posting guide >> > http://www.R-project.org/posting-guide.html >> > and provide commented, minimal, self-contained, >> > reproducible code. >> >> ______________________________________________ >> R-help at r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, >> reproducible code. > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve?