On May 22, 2007, at 9:17 AM, [EMAIL PROTECTED] wrote: > On Tue, 22 May 2007, David Harvey wrote: > > 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".
I think _scalar_ referred to the possible maps polynomial/square matrix/etc --> basering, and for this use I rather like that name. > 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 agree that this is the best method, though I think a unitless() or no_units() method would be good too. > 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? Perhaps, though I think it would be better implemented by having an alternate print mode for real intervals. One would probably then get into issues of propagating them symbolically through maxima... - Robert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
