rational solution in R [Software]

posted by mittyri – Russia, 2020-12-21 13:49 (135 d 09:05 ago) – Posting: # 22152
Views: 1,963

Hi Helmut,

» At least consistently giving not zero. ;-)
»

library(Rmpfr)
» prec <- 64
» x <- mpfr(0.5, prec) - mpfr(0.4, prec) - mpfr(0.1, prec)
» x
» 1 'mpfr' number of precision  64   bits
» [1] -2.77555756156289135106e-17
» y <- mpfr(-0.4, prec) - mpfr(0.1, prec) + mpfr(0.5, prec)
» y
» 1 'mpfr' number of precision  64   bits
» [1] -2.77555756156289135106e-17



I think the right solution is
install.packages("remotes")
remotes::install_github("bertcarnell/rational")
library(rational)
(rational(5L, 10L) - rational(4L, 10L) - rational(1L, 10L)) == 0
[1] TRUE


Interestingly but I did not find good solution using CRAN

Kind regards,
Mittyri

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