On Wed, 24 Mar 2010, William Dunlap wrote:
Should both parts of a complex number be printed
to the same precision? The imaginary part of 0
looks a bit odd when log10(real/imag) >=~ getOption("digits"),
but I'm not sure it is awful. Some people might
expect the same number of significant digits in the
two parts.
'significant digits' is documented in ?signif and xref-ed in ?print.
So, yes, the are 'printed to the same precision' for the definition
given of 'precision'. (One can argue that precision is relative to
the modulus, but this definition is a close approximation.)
From the NEWS for 2.4.0:
o Printing of complex numbers could misbehave when one of the
parts was large (so scientific notation was used) and the
other was so much smaller that it had no significant digits
and should have been printed as zero (e.g. 1e80+3e44i).
and 2.2.0
o signif() on complex numbers now rounds jointly to give the
requested number of digits in the larger component, not
independently for each component.
1e7+4i
[1] 10000000+0i
1e7+5i
[1] 10000000+0i
1e10 + 1000i
[1] 1e+10+0e+00i
getOption("digits")
[1] 7
...
--
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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