I hate significant figures. Use real error propogation and standard deviations instead. David
On 5/22/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > > > > > 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? > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] 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/ -~----------~----~----~----~------~----~------~--~---
