make check of R-alpha_2006-04-08_r37675 fails: qbeta

  Source directory:          .
  Installation directory:    /usr/local

  C compiler:                gcc  -g -O2 -std=gnu99
  Fortran 77 compiler:       g77  -g -O2

  C++ compiler:              g++  -g -O2
  Fortran 90/95 compiler:    g77 -g -O2

  Interfaces supported:      X11, tcltk
  External libraries:        readline, BLAS(ATLAS)
  Additional capabilities:   PNG, JPEG, iconv, MBCS, NLS
  Options enabled:           R profiling

  Recommended packages:      yes

44 (0) $ make
[...]

45 (0) $ make check
[...]
running code in 'd-p-q-r-tests.R' ... OK
comparing 'd-p-q-r-tests.Rout' to './d-p-q-r-tests.Rout.save' ...777,778d776
< Warning message:
< full precision was not achieved in 'qbeta'
make[3]: *** [d-p-q-r-tests.Rout] Error 1
[...]

46 (0) $ diff tests/d-p-q-r-tests.Rout.{save,fail}
3c3
< Version 2.3.0 alpha (2006-04-03 r37628)
---

Version 2.3.0 alpha (2006-04-08 r37675)

791a792,793

Warning message:
full precision was not achieved in 'qbeta'

1073c1075
< Time elapsed:  2.53 0.03 2.55 0 0
---

Time elapsed:  4.939 0.024 4.967 0 0

The (hopefully) interesting part of tests/d-p-q-r-tests.Rout.fail:

## Check q*(p* ( log ), log) = identity
All.eq(Rbeta,   qbeta    (log(Pbeta), shape1 = .8, shape2 = 2, log=TRUE))

[1] TRUE
Warning message:
full precision was not achieved in 'qbeta'

Please let me know if there is more I can provide to help trace this!

I suspect that this is related to recent changes in the zero-finder,
and that it is relatively benign. (If it is the effect that I'm
thinking of, then the warning is spurious, and it is mainly a matter
of whether we want to try to get rid of the warning or update the
.Rout.save file.)

I am not seeing it on my platforms (FC3 x86_64 and i686 Linux with gcc
3.4.5 and 4.1.0, i386 Windows and Solaris, with various compilers) and
the zero-finder changes postdate r37675 (and qbeta does not use it). I
think several other people are testing i686 Debian, including the
daiuly CRAN package checks ....

I suspect it is a real (and long-standing) problem of loss of accuracy
(2.2.1 did a check but did not report the results: it seems to be a
convergence failure looking at qbeta.c).  What compiler version is
this?

ATLAS is not involved.  You'll need to trace qbeta.c.