On Mon, Jul 23, 2012 at 9:52 PM, Aaron Meurer <[email protected]> wrote: > On Jul 23, 2012, at 12:33 PM, Sergiu Ivanov <[email protected]> > wrote: > >> On Mon, Jul 23, 2012 at 9:17 PM, Aaron Meurer <[email protected]> wrote: >>> On Jul 23, 2012, at 2:20 AM, Sergiu Ivanov <[email protected]> >>> wrote: >>> >>>> On Sun, Jul 22, 2012 at 11:44 PM, Aaron Meurer <[email protected]> wrote: >>>>> >>>>> Can you be more specific? Most likely, one of the results is "better" >>>>> than the other, and the algorithm should be fixed to always give it >>>>> regardless of ordering. >>>> >>>> FiniteSet._complement works as follows: >>>> >>>>>>> from sympy import FiniteSet >>>>>>> FiniteSet(1, 2, 3).complement >>>> (-oo, 1) U (1, 2) U (2, 3) U (3, oo) >>>> >>>> I'm not sure this result can be achieved more efficiently by a >>>> different approach then sorting the elements. >>> >>> This is the exact same as FiniteSet itself. Union's args do not need >>> to be sorted except within the printer. >> >> I was referring to the fact that, for example, FiniteSet(3, 1, >> 2).complement should return the same result. >> >> In other words, to get the complement relative to RR, one has to sort >> the numbers in the FiniteSet first, because otherwise one may get >> stuff like (-oo, 3) U (1, 2) U (2, oo). > > Well this answer is simply wrong.
Obviously; that's why one needs to sort the elements of the FiniteSet when computing the complement with respect to real numbers. Sergiu -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
