Le dimanche 8 janvier 2017 16:16:06 UTC+1, Dima Pasechnik a écrit : > > IMHO there ought to be possible to return "Unknown" as the result. > Indeed, in many cases such an exact computation is not feasible. >
ISTR that this discussion (binary vs "ternary" logic, "trools", or introduction of an "Unknown" truth value) has already been discussed *ad nauseam* on this list and on sage-support, with no conclusive results. Should this be discussed again, with a call for *VOTE* ? HTH, -- Emmanuel Charpentier > > On Saturday, January 7, 2017 at 9:54:36 PM UTC, vdelecroix wrote: >> >> Hello, >> >> Some symbolic expressions claim that they are not real >> >> sage: cos(pi/7).is_real() >> False >> sage: (exp(I*pi/7) + exp(-I*pi/7)).is_real() >> False >> >> But conversion to real floating points perfectly works >> >> sage: RR(cos(pi/7)) >> 0.900968867902419 >> sage: RR(exp(I*pi/7) + exp(-I*pi/7)) >> 1.80193773580484 >> >> I guess we could (and should) make it consistent. See also the related >> #16436. >> >> Vincent >> > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
