Problem with <= (less than or equal): not giving the expected result
FAQ 7.31 ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance Kliniekstraat 25 1070 Anderlecht Belgium 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 2016-04-05 13:34 GMT+02:00 Rainer Johannes <Johannes.Rainer at eurac.edu>:
Dear All, I have the following problem: I have a function in which I check if the difference between values is smaller or equal to a certain threshold. I however realized that I might get there some unexpected results:
abs(1 - 0.95) >= 0.05
[1] TRUE ## So that?s fine, but:
abs(1 - 0.95) <= 0.05
[1] FALSE Apparently, abs(1 - 0.95) is not equal to 0.05, which I find however quite disturbing. Along these lines:
abs(0.95 - 1) > 0.05
[1] TRUE
abs(0.95 - 1) < 0.05
[1] FALSE I guess that has to do with the floating point representation of the data? Is there something I miss or is there any solution to this? Thanks for any help! cheers, jo I tried this on different R-version (including 3.2.3 and 3.3.0 alpha); The R-version I used for the code above is:
sessionInfo()
R version 3.0.2 (2013-09-25) Platform: x86_64-unknown-linux-gnu (64-bit) locale: [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8 [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 [7] LC_PAPER=en_US.UTF-8 LC_NAME=C [9] LC_ADDRESS=C LC_TELEPHONE=C [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C attached base packages: [1] stats graphics grDevices utils datasets methods base
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