[R] general inverse solver?

[Stavros Macrakis]

On Tue, Feb 10, 2009 at 7:51 AM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> ...Also while Maxima is more sophisticated in terms of algorithms,

Glad to hear it... (I first worked on Maxima in 1971...)

> yacas is actually more sophisticated from the viewpoint of its language which borrows ideas from both imperative and prolog programming

It is true that Yacas has a nicer syntax for its pattern-matching
functionality than Maxima, but I think they are fundamentally very
similar.  In particular, as far as I can tell, neither does
backtracking or unification, so neither is very Prolog-like.

> and its interfaces are more sophisticated (it is one of the few CAS systems
> that developed an OpenMath interface) and its socket server is
> used by the Ryacas interface.

Maxima interfaces to a variety of other systems via sockets.  It does
not have an OpenMath interface (yet!), but I don't know how useful
that is compared to other linearized tree structures.

> yacas can also translate math expressions to TeX and do exact arithmetic.

Maxima can also output TeX and do exact rational arithmetic and
arbitrary-precision floating-point arithmetic.  Maxima also handles a
variety of cases which apparently Yacas doesn't, like factorization of
multivariate polynomials (seems pretty basic!), many special
functions, etc.  Maxima also has an active user and development
community.

           -s