On Mon, 31 Jan 2011, ken.willi...@thomsonreuters.com wrote:
For the complex-numbers bug, do you know a reliable way (besides looking
at version numbers) to determine whether the bug is present or absent in a
given build?
I know a way: See tests/complex.R in R-devel.
z <- 0.2853725+0.3927816i
z2 <- z^(1:20)
z3 <- z^-(1:20)
z0 <- cumprod(rep(z, 20))
stopifnot(all.equal(z2, z0), all.equal(z3, 1/z0))
## z^3 had value z^2 ....
I don't know what version of gcc was used in my build nor the optimization
flags, so I did a few test exponentiations z^n and the results look okay,
but maybe I'm not tickling the right bits.
--
Ken Williams
Senior Research Scientist
Thomson Reuters
Phone: 651-848-7712
ken.willi...@thomsonreuters.com
http://labs.thomsonreuters.com
On 1/31/11 1:48 PM, "Prof Brian Ripley" <rip...@stats.ox.ac.uk> wrote:
Two things have emerged in testing on x86_64 Fedora 14 which mean that
a recent R-patched is probably needed.
1) That OS uses zlib 1.2.5: that claims to be binary-compatible with
zlib 1.2.3 but is not, as we found (painfully) on Windows. The remedy
was to remap _all_ the symbols in R's own copy of zlib (not just those
zlib arranged to remap).
The symptoms were crashes using packages XML and rgoobi (both of which
link to zlib) and incorrect results in RJaCGH (which contains a copy
of zlib). There may well be other problems ....
2) Fedora 14 uses gcc 4.5.1. With CFLAGS containing the default -O2
or higher, HAVE_C99_COMPLEX was detected as false because there is a
(genuine) incompatibility between types Rcomplex and C99's double
complex. This means that R's fallback code is used, and regretably
that contains a serious bug in an 'optimization' by a colleague, so
z^n is incorrect for most complex z and integer n (and has been since
2.10.0). The remedy is to use R-patched or R-devel, or only optimize
to -O.
We've also seen incorrect results from package mvtnorm when C
optimization was -O3.
The upshot is that there is likely to be a 2.12.2 to fix these issues.
--
Brian D. Ripley, rip...@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
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--
Brian D. Ripley, rip...@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
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