Comment & Suggestion



Dear Maxima-Developers,


First let me thank you for all the work you are doing!
I'm impressed at how comprehensive this package is.

After using MacKichan's Scientific Workplace for a number of years,
when the license expired and the Maple Engine was taken out and only
the MuPad Engine was available, I had to find a new home for doing
math which is Maxima.
The most obvious difference was having to give up text-book like input.

I want to work in three areas:
	1. Differential Equations
	2. Nabla
	3. Tensors
For DEs I was looking for 'slope fields' and didn't find them with this search 
term (in Maxima-5_13.pdf and Maxima-Help 5.22.1 Manual).
For Nabla-Stuff I looked up Nabla and didn't find it with this search term 
except in a call to texput().
For Tensors I found three different packages.

I did find the slope-fields in 66 Plotdf under the name of 'direction field' but 
only after going through the total manual.
Eventually I found the Nabla material I was looking for (grad(), div(),curl(), 
laplace()) in Chapter 19 Differentiation in package 'vect' and embedded in 
function express().

With this experience I'd like to suggest including the search terms (i.e. slope 
field, nabla) in the manual and index and referring to where they are discussed 
- rather than not having them there at all. Not finding the search terms might 
give the impression that the package is unable to do the desired tasks - which 
isn't true.
And 66 Plotdf could possibly become part of 22 Differential Equations?
And 59 linearalgebra could possibly become part of 25 Matrices and Linear 
Algebra?

After reading up on Maxima tensor packages I get the impression that ctensor is 
the most complete and the most up to date of the three. Surprisingly I found in 
the package two functions (bimetric(),invariant2()) with the express 
information: *** NOT YET IMPLEMENTED *** in both sources. 

In order to get a faster grip on Maxima functions I created a MySql-database 
that collects their names (by now 260, growing), their chapter, package, 
explanation and page number in the manual which I'm willing to contribute. By 
doing so I found some function declarations in two places like:
dscalar() in '19 Differentiation' and '28 Ctensor'; rank() in '25 Matrices and 
Linear Algebra' and '59 linear algebra' which might not be intended.

I'm looking forward to many pleasant hours of using Maxima in my daily routine.

Kind regards

Joerg Rauh