Dear Ed,
Gnuplot is just a
plotting engine, though, isn’t it? You still have to do the analysis in
some language, right?
That’s true except for simple things- but there are Ruby bindings
available
for it.
Have you looked at Singular?
No, but I will. Thanks for the reference. I couldn’t find any bindings
on
the first page of Google results for “Singular Ruby”.
kan/sm1 is open source and free. It’s part of OpenXM
_http://www.math.sci.kobe-u.ac.jp/OpenXM_
(OpenXM (Open message eXchange for Mathematics)) .
Somewhere, they promise Ruby bindings for it, but these haven’t
materialised
for me so far ( maybe it’s a compiling problem though).
Maple and Mathematica aren’t free of course. When I am angry at their
syntax
I sometimes feel that software can be protected from potential users by
making it commercial 
Best regards,
Axel
