Duncan,
Thanks for your reply: given Petr's response, it seems the problem is
the interpretation by the printing code, not the actual representation
of the number. Given the representation, 1.817 would be correct, unless
at the working accuracy it is considered to be equal to 1.8165 (as
indeed I asked it to be).
I will have to find a workaround, or live with two sets of test results.
Ruth
On 10/03/2012 00:48, Duncan Murdoch wrote:
On 12-03-09 4:34 PM, Ruth Ripley wrote:
Dear all,
I have been running some tests of my package RSiena on different
platforms and trying to reconcile the results.
With Mac, the commands
options(digits=4)
round(1.81652, digits=4)
print 1.817
The value you're printing is 1.8165, so I believe Windows gets it right
using our "round-to-even" rule, but I'm not surprised that there are
differences. The value 1.8165 isn't exactly representable, so it's
somewhat random whether a system chooses to represent it slightly larger
or slightly smaller.
Duncan Murdoch
With Windows, the same commands print 1.816
I am not bothered which answer I get, but it would be nice if they were
the same. A linux box agreed with the Mac.
Mac sessionInfo():
R version 2.14.2 (2012-02-29)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
locale:
[1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] RSiena_1.0.12.205
loaded via a namespace (and not attached):
[1] grid_2.14.2 lattice_0.20-0 Matrix_1.0-4 tools_2.14.2
Windows (but 2.14.1patched was the same) sessionInfo():
R version 2.15.0 alpha (2012-03-08 r58640)
Platform: i386-pc-mingw32/i386 (32-bit)
locale:
[1] LC_COLLATE=English_United Kingdom.1252
[2] LC_CTYPE=English_United Kingdom.1252
[3] LC_MONETARY=English_United Kingdom.1252
[4] LC_NUMERIC=C
[5] LC_TIME=English_United Kingdom.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
Any enlightenment would be gratefully received.
Ruth
--
Ruth M. Ripley, Email:r...@stats.ox.ac.uk
Dept. of Statistics, http://www.stats.ox.ac.uk/~ruth/
University of Oxford, Tel: 01865 282857
1 South Parks Road, Oxford OX1 3TG, UK Fax: 01865 272595
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