using units in Maxima?



--- Barton Willis <willisb at unk.edu> wrote:

> > In his example, done in Mathcad, he includes units with 
> > his value assignments and calculations.  It it possible to do such
> > a thing in Maxima?  If so, how?  Thanks.
> > 
> > -Ron Crummett
> 
> Maybe something simple will work for you:
> 
> (%i1) l : 6.23 * 'feet$
> (%i2) w : 5.89 * 'feet$
> (%i3) area = l * w;
> (%o3) area=36.694699999999997*feet^2
> (%i4) subst(feet = mile / 5280,%);
> (%o4) area=1.3162412477043157*10^-6*mile^2

Definitely the simplest option.

> Alternatively, there is a 'units' package (try load(units)).
> But I don't know how to use the package or if it works.

There are two other "unit" packages in the contrib directory - Robert's
might be the better bet, since he is active in Maxima and could help
you debug it.  The other one I wrote (with a lot of help from Barton
et. al.) but while it is close to being at least functional in the
programming sense (there are some bugs I never did get ironed out) it
would take some polishing and is rather short on unit definitions and
advanced features.  There is quite a lot of email concerning both
options in the archives if you are inclined toward development :-).

I've switched focus and am currently trying to get a Units package
defined for the Axiom computer algebra system, but that project is
rather more long term and won't produce anything practical for a while.
:-/.

Cheers,
CY

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