On Monday 17 March 2008 07:11, Robert Dodier wrote:
> On 3/15/08, Alexey Beshenov <al at beshenov.ru> wrote:
>> /share/contrib/vector3d code is pretty clear, but it isn't documented in
>> texinfo (as far as I see). It seems that there are no other working
>> implementations of vector calculus stuff in Maxima. /share/vector/
>> contains something old and weird.
>>
>> I'll do a texinfo file for vector3d, okay?
>
> Before you get started on that, I'll recommend that you review the
> existing vector packages, of which I think there are three,
> vect, vector, and vector3d. They seem to implement overlapping
> but somewhat different collections of identities and what-not.
> Ideally we would determine what are the identities known to each
> package, and merge all the ones deemed useful into a single
> package, and get rid of the others. If you want to go into that,
> please go right ahead.
> But if all you want to do is write some documentation for vector3d,
> that's OK too. There is a plain-text file vector.usg which has some notes.
I found the current documentation a bit confusing. It says that
vectorsimp(...) from the package "vect" knows how to expand expressions
with "div", "grad", "curl" and "laplacian". But these operators are not
listed at the reference manual index, so it seems that only vectorsimp(...)
knows about them (?).
Am I right and only /share/contrib/vector3d stuff can actually compute
divergence, gradient, curl and laplacian? It defines functions div(...),
grad(...), curl(...), laplacian(...), but not operators, so it's not
compatible with vectorsimp(...). vector3d knows nothing about identities, it
just applies certain operators to given scalar or vector functions.
In my opinion, the basic needed functionality is computing gradient,
divergence, curl and laplacian in cartesian, cylindrical and spherical
coordinates. vector3d fits these needs. All we should do is to merge it with
vectorsimp(...) stuff, I think.
So we should add operators div, grad, curl/rot, laplacian and basic rules for
simplification, and maybe add rectangular and polar coordinates.
--
Alexey Beshenov <al at beshenov.ru>
http://beshenov.ru/
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