Assistance requested with basic Maxima commands.

"C. Frangos" wrote:

> 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.

Not currently.  You can convert strings to symbols however.

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

Yes.  The syntax is f(a1,..,an,[x]), where ai are the fixed arguments
and [x] is bound to a list of the variable arguments.  The ai can be empty.

>
>
> (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 ?
>

What does this do 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 (?).

Yes, I think stringout is what you want.

>
>
> (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)
>

This package has to be loaded before use.

>
> (7) From where can I buy Macsyma ?

The commercial version was sold on ebay at one time, and still may be sold
there.
Another address was posted on this list, look at the archives.

>
>
> 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)
>
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