But you can't create a constant Poly without giving the domain. Try something like the following (and, again, trace the code to see if there is a more direct way of learning the domain):
>>> Poly(1.2+var('x')) Poly(1.0*x + 1.2, x, domain='RR') >>> Poly(1+var('x')) Poly(x + 1, x, domain='ZZ') >>> Poly(1/S(3)+var('x')) Poly(x + 1/3, x, domain='QQ') >>> _.domain QQ On Friday, June 27, 2014 10:44:06 AM UTC-5, Aaron Meurer wrote: > > If you create a constant Poly, it picks the domain. You should look at > the source to see how it picks that. > > Aaron Meurer > > On Sat, Jun 21, 2014 at 10:48 AM, Christophe Bal <proj...@gmail.com > <javascript:>> wrote: > > Hello. > > > > I do not know if it is the case but I think that sympy should have a > domain > > method for expressions. This will avoid error like for example float > > calculations raising to 1 for example that wi-ould not be a natural but > a > > float. > > > > C. > > > > > > 2014-06-21 17:08 GMT+02:00 Saurabh Jha <saurab...@gmail.com > <javascript:>>: > > > >> I think that makes sense. I think this functionality is already > >> implemented in Polys module in some form. I am not able to pin point > it. > >> > >> > >>> > >>> First, it' unnecessarily slow. > >>> Just check whether f == round(f) for floats. > >>> > >>> Second, the question whether a float is integral or not borders on > >>> madness - you never know whether the answer "it's a natural number" > >>> comes from the round-off lottery or is genuine. > >>> > >>> Third, regular expressions aren't going to give any meaningful results > >>> for symbolic expressions, and the "Sym" in SymPy defines its mission > >>> statement: symbolic math. > >>> > >>> If you pursue a way to find out whether a *symbolic expression* is in > >>> ZZ, QQ, Complex, or whatever, then that would be worth thinking about. > >> > >> > >> > >> -- > >> You received this message because you are subscribed to the Google > Groups > >> "sympy" group. > >> To unsubscribe from this group and stop receiving emails from it, send > an > >> email to sympy+un...@googlegroups.com <javascript:>. > >> To post to this group, send email to sy...@googlegroups.com > <javascript:>. > >> Visit this group at http://groups.google.com/group/sympy. > >> To view this discussion on the web visit > >> > https://groups.google.com/d/msgid/sympy/ce634669-04e1-48ab-83b5-7f5c1884b0af%40googlegroups.com. > > > >> > >> For more options, visit https://groups.google.com/d/optout. > > > > > > -- > > You received this message because you are subscribed to the Google > Groups > > "sympy" group. > > To unsubscribe from this group and stop receiving emails from it, send > an > > email to sympy+un...@googlegroups.com <javascript:>. > > To post to this group, send email to sy...@googlegroups.com > <javascript:>. > > Visit this group at http://groups.google.com/group/sympy. > > To view this discussion on the web visit > > > https://groups.google.com/d/msgid/sympy/CAAb4jGmQzk3FqVpMCUDUhr8w%2ByiibM3fSz_eMJ0S1O_6_wqveQ%40mail.gmail.com. > > > > > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/d5c5d2f1-e19c-4010-9fd7-1008929c268a%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.