[R] Extending the accuracy of exp(1) in R

(Ted Harding) ted.harding at wlandres.net
Tue Nov 9 15:57:34 CET 2010

On 09-Nov-10 13:57:08, Hadley Wickham wrote:
>> Where the value of exp(1) as computed by R is concerned, you have
>> been deceived by what R displays ("prints") on screen. The default
>> is to display any number to 7 digits of accuracy, but that is not
>> the accuracy of the number held internally by R:
>> _exp(1)
>> _# [1] 2.718282
>> _exp(1) - 2.718282
>> _# [1] -1.715410e-07
> I encourage anyone confused about this issue to study
> http://en.wikipedia.org/wiki/The_Treachery_of_Images
> And to watch
> http://www.youtube.com/watch?v=ejweI0EQpX8
> Hadley

"YES"! And to really clinch the point, have a look at:


and perhaps also my own composition at:


What you *see* in treacherous (or any) images is marks on paper,
or on a computer screen, ...

What you *perceive* is different. Always. (Well, almost always:
you can make a deliberate effort to study the marks on the paper
as marks on paper).


E-Mail: (Ted Harding) <ted.harding at wlandres.net>
Fax-to-email: +44 (0)870 094 0861
Date: 09-Nov-10                                       Time: 14:57:31
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