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From: austern@ux5.lbl.gov (Matt Austern)
Newsgroups: comp.sys.handhelds
Subject: Re: HP48 units bug
Summary: Yes, fractional units can be useful
Message-ID: <7111@dog.ee.lbl.gov>
Date: 19 Sep 90 23:41:06 GMT
References: <1990Sep19.024034.15518@mintaka.lcs.mit.edu> <110540017@hpcvlx.cv.hp.com>
Sender: usenet@dog.ee.lbl.gov
Reply-To: austern@ux5.lbl.gov (Matt Austern)
Organization: Lawrence Berkeley Laboratory (theoretical physics group)
Lines: 32
In-Reply-To: paulm@hpcvlx.cv.hp.com (Paul J. McClellan)
X-Local-Date: Wed, 19 Sep 90 16:41:06 PDT

In article <110540017@hpcvlx.cv.hp.com>, paulm@hpcvlx (Paul J. McClellan) writes:
>Please explain to us what physical quantity is represented by the square
>root of a Newton.  The unit application was designed to solve useful
>problems in a reasonable amount of time and memory space, and fractional
>unit exponent support was intentionally omitted to achieve this.
>

In certain unit systems, the square root of a Newton (or, more
precisely, the square root of a Newton*meter^2) is a unit of electric
charge.  

More generally, I've seen fractional units quite often, in many
contexts.  (The other high-energy physicists on this group will, for
example, recognize the expression mu^(4 - epsilon), where mu has units
of mass or energy and epsilon is some small positive number.)

Fractional units aren't always useful, but some people find them
convenient for certain purposes.  It's dangerous to assume that the
unit system that is convenient for you is convenient for everyone!

I'm not complaining about the lack of support for fractional units.
(I noticed it a few months ago, posted it, and forgot about it.)
Indeed, this feature probably isn't important for most people, and
speed and space are important.  Still, I think that this should have
been mentioned in the manual.  The behavior of the unit conversion
commands doesn't match what the documentation says.  And that is the
definition of a bug, isn't it?
-- 
Matthew Austern    austern@lbl.bitnet     Proverbs for paranoids, 3: If 
(415) 644-2618     austern@ux5.lbl.gov    they can get you asking the wrong 
                   austern@lbl.gov        questions, they don't have to worry
                                          about answers.