correction: .....over the quotient field of the polynomial ring over the complex numbers....
2011/10/21 Urs Hackstein <urs.hackst...@googlemail.com> > Hi Simon, > > thanks a lot for your remarks. My expression doesn't contain I and thus the > definition of I as the generator of CC doesn't change anything. > > Well, the definition of f contains a lot of symbolic variables, so that > might be the problem. I don't define f at once, but succesively. Starting > with the fraction > > T12*T22*Z21*Z22/T1*T2*Z21+T1*T2*Z22, > > > I replace successively all symbolic variables by expressions with new > siymbolic variables, so that f grows larger and larger. > > Is there a possibility to have coefficients of symbolic variables and to work > over the quotient field of complex numbers at the same time.? > > > > Thanks a lot in advance, > > Urs Hackstein > > > > > 2011/10/20 Simon King <simon.k...@uni-jena.de> > >> Hi Urs, >> >> On 20 Okt., 13:08, Urs Hackstein <urs.hackst...@googlemail.com> wrote: >> > f.parent() gives indeed "Symbolic Ring". But at the beginning I defined >> > >> > P.<s> = CC[] >> > P.fraction_field() >> >> Then we really need to know how you define f. >> >> Recall that in the other thread on that subject, I pointed out how >> easy it is to start with a polynomial and end with a symbolic >> expression: The symbol "I" is a symbolic expression. It is recognised >> as an element of CC, but nevertheless its parent is the symbolic ring: >> >> sage: I in CC >> True >> sage: I.parent() >> Symbolic Ring >> >> Hence, when you add the generator s of the polynomial ring with I, >> then you obtain a symbolic expression, not a polynomial, even though >> the sum is recognised as an element of the polynomial ring: >> sage: P.<s> = CC[] >> sage: s.parent() >> Univariate Polynomial Ring in s over Complex Field with 53 bits of >> precision >> sage: (s+I).parent() >> Symbolic Ring >> sage: s+I in P >> True >> >> This can be avoided by explicitly defining "I" to be the generator of >> CC: >> sage: I = CC.0 >> sage: I >> 1.00000000000000*I >> sage: (s+I).parent() >> Univariate Polynomial Ring in s over Complex Field with 53 bits of >> precision >> >> Best regards, >> Simon >> >> -- >> To post to this group, send email to sage-support@googlegroups.com >> To unsubscribe from this group, send email to >> sage-support+unsubscr...@googlegroups.com >> For more options, visit this group at >> http://groups.google.com/group/sage-support >> URL: http://www.sagemath.org >> > > -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
