[R] make check failed on linux-amd64 using PGI compilers

[Liaw, Andy]

> From: pd at pubhealth.ku.dk
> 
> "Liaw, Andy" <andy_liaw at merck.com> writes:
> 
> > Dear R-help,
> > 
> > I am trying to build R-2.2.0-patched (2005-11-07 r36217) on 
> the head node of
> > a Scyld cluster (dual Opteron 250s) using PGI compilers 
> (v6.0).  I used the
> > flags suggested by Jennifer Lai on R-devel (taken from 
> R-admin, except that
> > I had to add -L/usr/X11R6/lib64 to LDFLAGS).  The build 
> went fine, but make
> > check-all failed when running tests/Examples/graphics-Ex.R, at:
> > 
> > > plot(1:2, xaxs = "i") # 'inner-axis' w/o extra space
> > > stopifnot(par("xaxp")[1:2] == 1:2 &&
> > +           par("usr")[1:2] == 1:2)
> > Error: par("xaxp")]1:2] == 1:2 && par("usr")[1:2] == 1:2 is not TRUE
> > 
> > The above looks a bit strange to me, as running the R built 
> as above,
> > par("xaxp")[1:2] - 1:2 gives
> > 
> > [1] -1.110223e-16 -2.220446e-16
> > 
> > Is my R build faulty?  I'd very much appreciate any advise.
> 
> Relative errors of 1 ULP would not ruin my sleep.  It's not obvious to
> me which is the floating point operation responsible for the effect,
> though, and it is a bit suspicious given that it should just be the
> x-range of the data.

It's the par() output that has storage mode "double", as that stores the
coordinates.  1:2 has storage mode "integer".

Those comparisons looked a bit suspicious to me.  Isn't it recommended time
and again on this list not to test for exact equality of numerics?
all.equal() of the above does return TRUE.

Andy

 
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