From ripley at stats.ox.ac.uk  Fri Aug  5 22:01:02 2005
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Fri, 5 Aug 2005 21:01:02 +0100 (BST)
Subject: [Rd] Tests of gcc-4.0.1
Message-ID: <Pine.LNX.4.61.0508051512210.30020@gannet.stats>

I had promised to report on tests of gcc-4.0.1, and have now tracked down 
all the outstanding issues.

I am comparing gcc3 (gcc-3.4.4 including g77) and gcc4 (gcc-4.0.1 
including gfortran) on FC3, both i686 and x86_64 (the latter both 64-bit 
and 32-bit builds).  All compiled from the sources (the FC3 update to 
3.4.4 was not out when I started this).

The bottom line is that 4.0.1 shows none of the serious errors that 4.0.0 
showed, but was always slower (usually 4-10% slower) than gcc3 and (see 
below) about 25 CRAN packages fail only about half of which are 
attributable to deficiences in the packages.

The differences between the outputs has shown some places where R is more 
sensitive to rounding errors than might have been thought.  Amongst these 
are

- ppr (that was known)
- lowess, which can be extremely sensitive to the number of iterations
   allowed, as shown by panel 8 in example(attenu).
- contouring, in particular the exact place contour labels are placed.
- str, which depended on a test ob == signif(ob, digits.d), and signif()
   was unnecessarily causing rounding error by dividing by a negative power
   of 10 (now fixed).
- the extreme test in example(smooth.spline), which showed quite large
   differences.

Amongst CRAN packages:

RSvgDevice is said to have invalid C

acepack, deldir, fMultivar, fOptions, fSeries, frailtypack, gap, gcmrec, 
hmm.discnp, labdsv, survrec

have invalid Fortran. (Most of these have been reported to the maintainers 
some time ago.)

Geneland infinite loops
NISTnls, gss, relsurv fail their tests
SparseM, asypow, mvtnorm, party, subselect  segfault
ade4 has an LAPACK error (similar to those seen before)

-- 
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



[Rd] Tests of gcc-4.0.1
Prof Brian Ripley