[R] long integer handling

[Rui Barradas]

Hello,

You can compute the exact result with package Rmpfr.
See ?mpfr and [1].


library(Rmpfr)

two <- mpfr(2, precBits = 64)
two^64 - 1
#1 'mpfr' number of precision  64   bits
#[1] 18446744073709551615



[1] https://www.mpfr.org/

Hope this helps,

Rui Barradas

Às 01:44 de 14/11/20, Yousri Fanous escreveu:
> I want to calculate 2^64-1 which is
> 18446744073709551615
> 
> I set the following options to prevent scientific notation
> options("scipen"=100, "digits"=4)
>> x<-2^64 -1
>> x
> [1] 18446744073709551616
> 
> This is not correct. There seem to be still some approximation happening.
> How can I get the correct result?
> 
> Yousri
> IBM Canada ltd
> Software developer
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>