On Tue, 22 May 2007, David Harvey wrote:
>> 1*meters + 2*meters*meters : NOT OK.
>> 1*meters + 2*feet = ... in feet or meters? (I say meters)
>
> I say metres.
Not my fault you can't spell. ;)
William: I don't like the word "scalar". That may be because much of my
experience with PHP and PERL -- where there are scalars and arrays. I'd like
it to be called something like "unitless" or "value". However, since I did a
fair amount of tutoring for physics and engineering courses, being able to just
throw away the units is deeply disturbing to me, for the following reason:
> a = 5*meters
> b = 2*feet
> c = a*b; print c
10 feet*meters
> d = a*meters(b)
25.4 meters^2
> c == d
True
> print c.value()
10
> print d.value()
25.4
I would almost rather the user have to multiply by the inverse units. I know
almost nothing about chemistry... but last time I took a chemistry class, it
was nearly trivial because I'd gotten so used to fiddling with units: if the
units come out right, the answer is almost certainly correct.
Since we're on this topic: anybody who cares about units probably cares about
significant figures, too. Should the units classes do book-keeping on
significant figures?
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