Assistance requested with basic Maxima commands.

Hi all,

I am currently running Maxima 5.9.1 on a suse linux 9.2 machine. I am
trying to convert my Matlab/Matlab symbolic toolbox (uses Maple
engine), etc, to Maxima.

Any assistance with the following would be much apprecated:

(1) Is it possible to synthesize a command to convert a string into a
    valid expression, and then evaluate this using ev() ? The command
    string(expr) does the opposite, converts an expression to a string.

(2) Is it possible to write functions with a variable number of input
    variables ? (in Matlab I use varargin).

(3) Is it possible to plot a matrix x versus a vector t as in Matlab:
    plot(t,x) ?

(4) There does not seem to be a pause function as in Matlab ?

(5) I wrote a function which runs for quite some time. Just before the
    function exits I want to use a command to save all the computed
    variables into a file and load them later into Maxima for
    inspection. Is there such a command (?).

(6) Some functions do not seem to be defined (?):

(%i1) fullratsubst([x1=1,x2=2],x1^2-x2);
                                                    2
(%o1)              fullratsubst([x1 = 1, x2 = 2], x1  - x2)
(%i2)

(7) From where can I buy Macsyma ?

Regards,

C. Frangos.

-- 
Constantine Frangos.
Professor
Dept. of Mathematics and Statistics
University of Johannesburg
Auckland Park Kingsway Campus
P O Box 524
Auckland Park 2006
South Africa

Tel: +27-11-489-2452
Fax: +27-11-489-2832
e-mail: cf@rau.ac.za (work)
        cfrangos@telkomsa.net (home)