The matlab symbolic toolkit roughly works like this.
I am working from memory so I may have details wrong.
declare some symbolic variables like
x= symbol("x")
y= symbol("y")
then the matlab expression x+y is (by virtue of
generic, object-oriented blah blah) converted to
a symbolic version of addition.
There are some hacks to allow symbols in matrices, making
the whole enterprise much slower.
The genericity is only partial, and stuff like
x+1
fails.
You need to do x+symbol("1").
I count this, and some other features of the matlab symbolic
toolkit as "bugs".
So: you could do it all with strings + changing Octave
to have generic symbol types that go off to maxima and
occasionally return back to Octave data structures.
Why do it at all?
A person who loves Octave may see this as a very low-cost
introduction to symbolic computing.
Is it going to be better than a real computer algebra system
interface that links to high-quality back-end math?
I doubt it.
RJF
James Amundson wrote:
>On Thu, 2003-11-20 at 10:02, Richard Fateman wrote:
>
>
>>On the topic of Octave, which I gather is a GPL version of Matlab...
>>How hard would it be to make Octave be a front end for Maxima,
>>similar to Matlab with symbolic toolkit being a front end for
>>Maple? I have only given this 15 seconds of thought, but maybe
>>someone familiar with Octave can say something.
>>RJF
>>
>>
>
>I use Octave every day. I definitely think that some sort Maxima-Octave
>link would be useful. Even though I have thought about linking the two
>quite a bit, I still have conceptual questions about how the link should
>work. Unfortunately, I have not seen the Matlab symbolic toolkit.
>
>Somebody has already presented some Maxima-Octave code on the Octave
>list. It allows Octave to send a string to Maxima, which evaluates it
>and returns another string. I don't see how that would be helpful at all
>-- why not just have one window running Octave and another running
>Maxima? The basic problem is that Octave doesn't really deal with
>symbolic data. Perhaps we could have Maxima return expressions in Octave
>form in such a way that Octave would evaluate them, but I'm still not
>really sure how helpful that would be.
>
>Since Maxima deals with numerical *and* symbolic data, it might make
>more sense to have Maxima operate as a front end to Octave. There are
>issues with this approach also: doing purely numerical operations in
>Maxima is annoying. Expressions tend to end up partially symbolic, e.g.,
>(C1) 1.1 + sqrt(2);
>
>(D1) SQRT(2) + 1.1
>
>How would you imagine the interface working?
>
>--Jim
>
>P.S. There are also a set of technical issues involved in linking Maxima
>and Octave. I see multiple ways of solving them, so I don't think there
>should be any insurmountable problems there.
>
>
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