On Sat, Oct 9, 2010 at 2:38 PM, Joshua Wiley <jwiley.ps...@gmail.com> wrote: > Hi Steven, > > As near as I can tell, no precision is lost. R is just being > courteous and not excessively filling our consoles. Try: > > print(airports[1,"latitude_deg"], digits = 22) > > which is the most digits R will print (although internally it can > store more I believe).
Dr. Heiberger was kind enough to point out to that the maximum is 53 binary digits, as stated in the R FAQ 7.31: http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f Slides by the same from the recent UseR! 2010 conference also provide further explanation: http://user2010.org/slides/Heiberger.pdf One library that allows further precision is Rmpfr based on: http://www.mpfr.org/ To give a small example borrowing the sprintf() display from Dr. Heiberger's slides: > library(Rmpfr) > sprintf("%+17.17f", 2/3) [1] "+0.66666666666666663" > mpfr(2, 260)/3 1 'mpfr' number of precision 260 bits [1] 0.66666666666666666666666666666666666666666666666666666666666666666666666666666685 > My sincerest apologies for the previous misinformation. Josh <snip> ______________________________________________ R-help@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.
