Hi,
is there a possibility to completely turn off
this internal CRE business? It causes just a
never-ending stream of problems. (Just remember
the apparently forgotten gf-package, which is
in its most important functions not working because
of CRE-problems.)
Now we got rid off the gf-package, but Maxima is
apparently fully under-specified w.r.t. handling
of polynomials. On the main documentation page
for polynomials one finds the empty sentence
Polynomials are stored in Maxima either in General Form or as Cannonical Rational Expressions (CRE) form.
The latter is a standard form, and is used internally by operations such as factor, ratsimp, and so on.
In other words, no information is available when a polynomial suddenly becomes a CRE-vampire (looks
like a polynomial, but is not really a polynomial)?
I guess the whole thing is historical baggage?
Apparently there are no flags to force Maxima to always use just one representation?
By the way, the nice idea of showing with the output what type it is, doesn't
work and has never worked: The documentation of for example gcdex says
(%i1) gcdex (x*(y + 1), y^2 - 1, x);
1
(%o1)/R/ [0, ------, 1]
2
y - 1
but I have never seen such output-annotations (neither with CLisp nor with Ecl).
So apparently the only possibility is to use totaldisrep at some places,
until the current problem goes away, and to wait until the next problem shows up,
where then some further totaldisrep have to be placed somewhere, and so on?
Seems to be the case, but I wanted to be sure, and also wanted
to mention this problem.
Oliver
--
Dr. Oliver Kullmann
Computer Science Department
Swansea University
Faraday Building, Singleton Park
Swansea SA2 8PP, UK
http://cs.swan.ac.uk/~csoliver/