matrices and expressions

[Johan Rutgeerts]

Hi,

I only just started using ginac and there's some things about matrices
and their relation to expressions that I do not understand.

As for instance:

why does GiNaC::unity_matrix return a GiNaC::ex ?
or why does A + B with A and B both a GiNaC::matrix return a GiNaC::ex?

And how do I convert such a GiNaC::ex to a matrix? Can this be done?



Greetings,

Johan Rutgeerts