[R] build on Irix failed reg-tests

[Prof Brian Ripley]

I think NA+0 should be special, though.  All of mine give

> NA+NaN
[1] NA
> NaN+NA
[1] NA

That's with four separate compilers on Sparc-Solaris as well as Windows
and Linux i686.

I have long wondered why it works ....


On Wed, 17 Mar 2004, Liaw, Andy wrote:

> > From: Thomas Lumley [mailto:tlumley at u.washington.edu] 
> > 
> > On Wed, 17 Mar 2004, Liaw, Andy wrote:
> > 
> > > Dear R-devel,
> > >
> > > Has anyone seen this problem?  We tried building R-1.8.1 
> > (and R-1.9.0 alpha
> > > 2004-03-17) on an Irix 6.5 box using
> > >
> > > ./configure CC="cc -64" F77="f77 -64" --with-tcltk=no 
> > --enable-R-shlib
> > >
> > > make check failed because NA + 0 gave NaN instead of NA.  
> > I've tried both
> > > 32- and 64-bit build, with and without --enable-R-shlib.  
> > The same symptom
> > > occur in all cases.
> > >
> > 
> > I haven't seen it before, but it looks to me as though arithmetic.c
> > assumes that adding a number to a NaN gives the same NaN 
> > back, (NA is the
> > NaN with lower word 1954).  That is, we just do
> > #ifdef IEEE_754
> >             REAL(ans)[i] = REAL(s1)[i1] + REAL(s2)[i2];
> > #else
> > 
> > This doesn't look as thought it is guaranteed to work, though 
> > it does on
> > most machines.  It clearly can't work where both operands are NaN, so
> > under OS X I get
> > > NA+NaN
> > [1] NA
> > > NaN+NA
> > [1] NaN
> > 
> > 
> > 	-thomas
> > 
> 
> On our Opteron I get:
> 
> > NA+NaN
> [1] NaN
> > NaN+NA
> [1] NA
> 
> OK, now I'm really confused...
> 
> Andy
>  
> 
> 
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-- 
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