[Rd] make check on DU4 with R-1.1.0 snapshot

Prof Brian D Ripley ripley@stats.ox.ac.uk
Sat, 3 Jun 2000 06:23:41 +0100 (BST)

On Fri, 2 Jun 2000, Albrecht Gebhardt wrote:

> On Fri, 2 Jun 2000, Albrecht Gebhardt wrote:
> > On Fri, 2 Jun 2000, Albrecht Gebhardt wrote:
> > 
> > > 
> > > I just tried the rsync version of R-1.1.0 on one of my alphas:
> > > It compiles without problems (gcc/g77 2.95.2, system is DU4.0E)
> > > .........
> > > 
> > > I compiled --whithout-dxml, so I'm not using any special numeric library.
> > > 
> > 
> > Sorry I mixed something up in my report: In this compile I used the alpha
> > specific DXML library, in my rpms I omit it with --without-dxml (because
> > it sometimes crashes). I will try once more now without dxml, may be this
> > changes something, don't know if it gets used at all in the svd code.
> > 
> That was the reason. Now without DXML I pass the test without modifying
> Eps:

Nevertheless, the tolerance was too low. Most machines (e.g. Linux, 
Solaris and Windows) are giving errors of 8 or 9 times the 
machine precision, and with dxml you got 10x (and this failed as
Eps was exactly 10x). eigen's help page has tolerances of 60x and 1000x,
and I've given svd's 100x.


> So may be it is better do disable dxml support by default in ./configure?

Well, what does dxml support do for you?  Making the errors 1x machine
precision larger than without is hardly critical.  On the other hand, I am
not convinced that these optimized blas operations are worthwhile for all
but the most unusual uses of R.

On the other hand, I think it would be worth omitting the check for
-ldxml and -latlas except on appropriate platforms (whatever they are).


Brian D. Ripley,                  ripley@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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