Bioequivalence and Bioavailability Forum • rational solution in R

rational solution in R [Software]

posted by mittyri – Russia, 2020-12-21 14:49 (2008 d 05:08 ago) – Posting: # 22152
Views: 27,304

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

Complete thread:

Spreadsheet failures, any recent examples? ElMaestro 2019-07-18 13:43 [Software]
- Spreadsheet failures, any recent examples? Ohlbe 2019-07-18 14:32
  - Spreadsheet addiction Helmut 2019-07-18 16:12
    - Nasty beast Ohlbe 2019-07-18 17:30
      - Nasty beast Helmut 2019-07-18 20:26
        
        Nasty beast Ohlbe 2019-07-19 11:32
        
        Nasty beast ElMaestro 2019-07-19 12:32
        
        Decidedly off topic Ohlbe 2019-07-19 13:38
        
        OT: R limbo 101 Helmut 2019-07-19 13:00
    - Spreadsheet addiction Shuanghe 2019-07-18 18:59
      - Spreadsheet addiction Helmut 2019-07-18 20:04
        
        OT: Spreadsheet addiction Shuanghe 2019-07-19 12:41
        
        OT: Spreadsheet addiction Helmut 2019-07-19 14:29
        
        OT: Spreadsheet addiction nobody 2019-07-19 15:53
        
        OT: Spreadsheet addiction Helmut 2019-07-19 19:32
  - Spreadsheet etc. failures zizou 2019-07-20 00:18
    - As designed ☺ Helmut 2019-07-20 02:12
      - As designed ☺ ElMaestro 2019-07-20 09:08
        
        To round or not to round… Helmut 2019-07-20 12:53
        
        To round or not to round… ElMaestro 2019-07-20 19:59
        
        floating-point math is always more complex than you think it is mittyri 2019-07-20 22:43
- Spreadsheet failures, any recent examples? Ohlbe 2020-12-10 18:43
  - Floating point arithmetic, again Helmut 2020-12-10 19:12
    - Floating point arithmetic, again ElMaestro 2020-12-10 19:40
      - Floating point arithmetic, again Ohlbe 2020-12-10 20:18
        
        Floating point arithmetic, again ElMaestro 2020-12-10 21:38
        
        Floating point arithmetic, again Ohlbe 2020-12-10 21:46
        
        Floating point arithmetic, again ElMaestro 2020-12-10 22:05
        
        Depressed Ohlbe 2020-12-10 23:35
        
        Depressed ElMaestro 2020-12-11 07:59
    - Floating point arithmetic, again Ohlbe 2020-12-10 20:13
  - From bad to worse Ohlbe 2020-12-10 22:11
    - From bad to worse mittyri 2020-12-11 00:22
    - All is good Helmut 2020-12-11 00:36
      - Float is float PharmCat 2020-12-18 20:53
        
        Float is float! Helmut 2020-12-20 23:27
        
        rational solution in Rmittyri 2020-12-21 13:49
        
        related stuff Helmut 2021-01-14 12:53
        
        related stuff SDavis 2021-02-09 12:02
        
        related stuff ElMaestro 2021-02-09 19:55