On Saturday, June 9, 2018 at 7:44:45 AM UTC-7, William wrote: > > That "QQ(1) // QQ(2)" returns 1/2 in Sage is surely a mistake.
It may be a mistake, but I am very happy with the consequence. This is what I'd expect // to do on the rationals. FWIW in magma: > 5 div 2; 2 > R:=pAdicRing(7); a:=R!7; > a div a; 1 + O(7^19) > a div a^2; Runtime error in 'div': Division is not exact I'm quite happy with that. It gets a little weird with polynomial rings: > R<x>:=PolynomialRing(Rationals()); > (x+1) div x; 1 > R<x,y>:=PolynomialRing(Rationals(),2); > (x+1) div x; Runtime error in 'div': Argument 2 does not divide argument 1 but generally I find I need the "division in integral domain with error if element is not divisible" operation quite a bit more than "euclidean division without reporting the remainder directly". > It > might be my fault -- I have a vague memory of making this choice > (probably 14 years ago!). Why it should be 0: > > $ python3 > Python 3.5.2 (default, Nov 23 2017, 16:37:01) > [GCC 5.4.0 20160609] on linux > Type "help", "copyright", "credits" or "license" for more information. > >>> 2.5 // 3.5 > 0.0 > > (also, it's called "floor division"!) > > Fortunately, for sage floats // is an error, rather than a wrong answer: > > sage: 2.5 // 3.5 > TypeError: unsupported operand parent(s) for //: 'Real Field with 53 > bits of precision' and 'Real Field with 53 bits of precision' > > > > > > > -- > > 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+...@googlegroups.com <javascript:>. > > To post to this group, send email to sage-...@googlegroups.com > <javascript:>. > > Visit this group at https://groups.google.com/group/sage-devel. > > For more options, visit https://groups.google.com/d/optout. > > > > -- > William (http://wstein.org) > -- 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.
