Hi,
> The error message is uniformative, but given that > 'get_rational_solutions2' is not visible here _some_ error is > expected. Oh right, I can not call "get_rational_solutions2" because it is not exported by the domain. And importing does does not change that fact. (It indeed was too late.) The aldor compiler would have told me that by an informative message: [L43 C5] #1 (Error) There are no suitable meanings for the operator ... Well, then I need to write a package first for computing rational roots of polynomials. I hoped that a System like Axiom already had such a functionality. I tried to extract the function from 'ElementaryRischDEX' and put the new package here: https://github.com/raoulb/fricas_code/tree/master/ratroots At the moment it compiles, I consider this already a small success. But the exported functions are not really what I think the should be. The simplest function should maybe have a signature like: rationalRoots: (Poly(R), Symbol) -> List(Frac(R)) Or maybe not. I have no idea what a the perfect and appropriately generalized function should look like. Without such a functionality, I can not continue :-/ > > > Maximal root is well defined only if coefficients are numbers. > > > > The polynomial is univariate f.e over Q, so my coefficients > > are indeed numbers. > > Even that is tricky: your extension has multiple embeddings into > complex numbers. The set of real root and maximal real root > depends on the embedding of coefficient field. So if you really > need maximal root, you need to fix the embedding. Uhm, ok. > Yes, it ATM it is internal -- I needed rational roots for computing > integrals and apparently there was no usable function in sight, > so I wrote it. Current version is specialized for expressions > (I wrote exactly what was needed for integration), but the method > works as long as 'reducedSystem' works, that is base ring must > satisfy 'LinearlyExplicitRingOver(Integer)' (alas, for > RealClosure(Fraction(Integer)) 'reducedSystem' is unimplemented). Then the main purpose of "LinearlyExplicitRingOver" is to provide "reducedSystem", I see. Importing the RationalRoots package at least makes my other code compile. Thanks so far. -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/groups/opt_out.
