That is more or less FAQ 7.31: http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-the se-numbers-are-equal_003f
------------------------------------------------------------------------ ---- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 thierry.onkel...@inbo.be www.inbo.be To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey -----Oorspronkelijk bericht----- Van: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] Namens iuhz7j...@sneakemail.com Verzonden: vrijdag 17 april 2009 16:15 Aan: r-help@r-project.org Onderwerp: [R] Modular Arithmetic Error? Hi, I'm using the '%%' operator in some code, and am running into the following erroneous outcome: > 1.2 %% 0.2 [1] 0.2 Unless I'm very mistaken, the result should be 0 (indeed, 12 %% 2 does result in 0). Furthermore: > 1.20000000000000001 %% 0.2 [1] 0.2 > (1.2+1e17) %% .2 [1] 0 Warning message: probable complete loss of accuracy in modulus (Warning comes up only when it is giving a closer-to-correct answer) What makes it even stranger is this result: > (1.2 %% 0.2) == 0.2 [1] FALSE Does anybody know what's going on here? This seems like very bad behavior. Thanks, Peter ______________________________________________ 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. Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver weer en binden het INBO onder geen enkel beding, zolang dit bericht niet bevestigd is door een geldig ondertekend document. The views expressed in this message and any annex are purely those of the writer and may not be regarded as stating an official position of INBO, as long as the message is not confirmed by a duly signed document. ______________________________________________ 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.