[R] Installing R on RedHat7.0
Prof Brian D Ripley
ripley at stats.ox.ac.uk
Fri Nov 3 23:43:13 CET 2000
On Fri, 3 Nov 2000, Tom Wainwright wrote:
> Thanks! Building from source worked, and the demos all run. Several
> others report that R runs smoothly on RedHat7.
> However, not all the tests in $R_HOME/tests succeed. When I do "make
> test-Examples" in that directory, it fails executing "base-Ex.R" in the
> "eigen" section, with the error:
> Error: abs(sm %*% V - V %*% diag(lam)) < 60 * Meps is not TRUE
> This appears to be a numerical precision problem. Checking, Meps (i.e.
> .Machine.double.eps) is 1.084202e-19. Is this a reasonable value for a
> Pentium III?
No. .Machine$double.eps should be about 2e-16. An i686 does not have
19 digits of precision. Here's what gcc-2.95.2 gives on a PIII under
> If I rerun test-Examples, all the remaining tests complete with no problem.
> Similarly, make test-Specific fails during arith-true.R, with many tests
> returning FALSE.
> Have others who run R on RedHat7 run these tests? It seems that either
> there's a serious compiler problem, or the .Machine variables are getting
> set wrong, or I have a hardware problem.
The likely story is that that beta compiler is even farther from
IEEE-compliant than is usual for gcc on Linux. Some of us are
too nervous about it to even try an installation.
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 272860 (secr)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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