"Markus" <markus / reality.com> schrieb im Newsbeitrag
news:1097901288.21256.339.camel / lapdog.reality.com...
> On Fri, 2004-10-15 at 17:58, trans. (T. Onoma) wrote:
> > On Friday 15 October 2004 07:23 pm, markus / reality.com wrote:
> > | >     puts 0.5.round             #=> 1
> > | >     puts sprintf("%.0f", 0.5)  #=> 0
> > |
> > |      Both are (IIRC) ISO 31-0 conformant, but one uses ISO 31-0 B.3
rule A
> > | and the other uses ISO 31-0 B.3 rule B.
> > |
> > |      That said, one of the rules (the one sprintf uses, to round
down
> > | following even digits is an abomination and should be eliminated
from the
> > | face of the earth.  nnn.nn5 should ALWAYS round up and rounded
values
> > | should not be re-rounded (which is what the contrary rule assumes is
> > | happening).
> >
> > Apparently the idea of even vs. odd rounding was to help prevent
"inflational"
> > rounding --successive rounding pushing values upward. I think K&R
actually
> > supported the idea. I'm not sure how I feel about it.
>
>      Yes, that's exactly why it's there.  But there are several reasons
> (e.g. Benford's Law http://mathworld.wolfram.com/BenfordsLaw.html) why
> it doesn't even work for its intended purpose.  The real answer is to
> not re-round the data.
>
>      As for developing strong feelings about it, all you need to do is
> work downstream from someone who swears by it and try to do some valid
> numerical analysis.  The only person I ever knew with a worse lament was
> a friend who worked downstream of an astronomy professor (who should
> have been emeritusized years before) that routinely converted his images
> to jpeg "to save disk space."

A real "star destroyer"... :-))

*chuckle*

    robert