On 7/16/07, C Y <smustudent1 at yahoo.com> wrote:
> Robert, are you still developing your package?
Well, I haven't spent much time on ezunits lately,
and it is limited in scope, and there is no documentation,
but it works OK so far as I can tell.
For the record, ezunits represents dimensional quantities
as foo ` bar where foo is nondimensional and bar is the unit
of foo, e.g. a ` m, b ` m/s, c ` W/m^2.
ezunits adds dimensional quanitites by looking for common units,
but does not complain if some quantities have different units.
Dimensional quantities are multiplied by multiplying the
nondimensional parts and units separately, likewise exponents.
ezunits introduces a "dimensional" declaration; if not declared
as such, symbols are assumed by ezunits to be nondimensional.
ezunits also implements a means of declaring the nondimensional
quantity and units for symbolic, dimensional quantities.
The emphasis thus far has been on algebraic properties of
dimensional quantities, and I intend to continue in that direction
by introducing rules for integrals, derivatives, maybe other stuff
(plotting comes to mind).
ezunits has a test script, rtestezunits.mac, which has some examples.
batch(rtestezunits, test) runs the script. At present all tests pass
with CVS Maxima.
ezunits has no built-in units, and no provision for unit conversion.
I'll probably get around to that stuff sooner or later.
There exists a Maxima package for dimensional analysis;
probably ezunits should cooperate with that, also.
FWIW
Robert Dodier