R help - Sep 2004 - noncommutative addition: NA+NaN != NaN+NA

Hi guys.

Check this out:
>  NaN +NA
[1] NaN
>  NA + NaN
[1] NA

I thought "+" was commutative by definition.   What's going on?
>  R.version
          _
platform powerpc-apple-darwin6.8
arch     powerpc
os       darwin6.8
system   powerpc, darwin6.8
status
major    1
minor    9.0
year     2004
month    04
day      12
language R
>
(Both give NA under linux, so it looks like a version-specific issue).


-- 
Robin Hankin
Uncertainty Analyst
Southampton Oceanography Centre
SO14 3ZH
tel +44(0)23-8059-7743
initialDOTsurname at soc.soton.ac.uk (edit in obvious way; spam precaution)

On Tue, 7 Sep 2004, Robin Hankin wrote:
> Check this out:
I am unable to reproduce it on any of the 7 different systems I checked
(Solaris, Linux, Windows with various compilers).
> >  NaN +NA
> [1] NaN
> >  NA + NaN
> [1] NA
> 
> I thought "+" was commutative by definition.   What's going
on?
It is clearly not under your compiler/OS.  We could add a configure test 
for broken systems and fix it in arithmetic.c but it hardly seems 
worthwhile.
> >  R.version
>           _
> platform powerpc-apple-darwin6.8
> arch     powerpc
> os       darwin6.8
> system   powerpc, darwin6.8
> status
> major    1
> minor    9.0
> year     2004
> month    04
> day      12
> language R
> >
> 
> (Both give NA under linux, so it looks like a version-specific issue).
Linux on that hardware?  It might be a chip issue.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

At 06:17 07/09/2004, you wrote:

>Hi guys.
>
>Check this out:
>
>>  NaN +NA
>[1] NaN
>>  NA + NaN
>[1] NA
>
>I thought "+" was commutative by definition.   What's going
on?
In my version, both cases is NA:

 >  NaN +NA
[1] NA
 > NA + NaN
[1] NA
 >
R.version
          _
platform i386-pc-mingw32
arch     i386
os       mingw32
system   i386, mingw32
status
major    1
minor    9.1
year     2004
month    06
day      21
language R




Bernardo Rangel Tura, MD, MSc
National Institute of Cardiology Laranjeiras
Rio de Janeiro Brazil