> On 24 May 2017, at 04:24, M Kim <mkim0...@gmail.com> wrote: > > To the R development team: > > First of all, thank you so much for maintaining wonderful R software. > > Perhaps, Dr. Ahn has just reported an error on the wilcox.test() function, > and suggesting that an error may arise from abs() and rank(). > > > I just had a quick check that the problem may come from the precision of > the results of arithmetic functions. > > > 87.7-89.1+1.4 > # > 87.7-89.1+1.4 > # [1] 8.437695e-15 >
R FAQ 7.31. See https://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f Berend > I checked that do_arith() in arithmetic.c is using double type (8 byte) for > PLUSOP, MINUSOP, TIMESOP, DIVOP etc. > > https://github.com/wch/r-source/blob/f68b30e3b5479d84adbff516d48d4722a574dc82/src/main/arithmetic.c > > > I have two thoughts: > > (1) in the rank() function, we may round at less than 14 decimal places by > default? > > (2) using long double type (10 byte) instead of double type (8 byte) by > default in the arithmetic function could be helpful for preventing > embarassment? > > Perhaps, R may provide the arithmetic function with various variable types, > if some application needs. > > > Thanks. > > Min-hyung > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
