polynomial arithmetic over ginac

[Parisse Bernard]

> 
> I am a bit curious as to how you plan to use GiNaC as a CAS for PDAs? GiNaC
> is meant to be
> used  on a workstation with a c++ compiler, something I'm sure
> you will have a hard time getting to run on a PDA given the memory limits.
> Also, that would
> require a text editor etc. PDAs are notoriously hard to use for programming
> purposes, given
> they have a small keyboard (if they have one at all) and small screen. A
> completely different
> experience from working on a workstation, I can assure you.
> In fact, to make it useful on a PDA, the most important thing is actually a
> good user interface.
> And you will have a hard time designing a user interface that is different
> from the calculator
> metaphor. A calculator is not very suited for the more elaborate
> calculations, where you actually
> have to write a little program to solve the problem.

I disagree with this. I'm the main programmer of the HP49G and HP40G
calculators CAS and I believe that a calculator is well suited for
little programs, that's not much different from writing a small program
in a CAS 
like Maple or MuPAD. 
The main problem with graphing calculators (especially the HP4xG) is the
processor speed (about 1000* slower than my laptop), not the programming
environment (e.g. you have a debugger, you can put breakpoints and exec
your program step by step, and view the current stack).
If we want to replace one day the proprietary CAS with GPL'ed CAS, we
must 
start by providing a good solution for the educationnal market and the
non-mathematician users.

> 
> I have a little experience trying this. I ported yacas (a GPL'ed CAS) over
> to the Psion series organisers.
> But it is too clumsy to use right now (console on a PDA ;-) ). The dream is
> of course
> to be able to do some math stuff while away from your computer (perhaps
> sitting outside
> in a park in the sun somewhere ;-) ). The experience disappointed me a bit.
> You need a good
> user interface first.

Well, if we provide a good library, I'm sure we will find hardware
vendors ready to develop interfaces for the educationnal market.
We don't need the interface first, we need to meet the specifications
of the education market.