Mark Dickinson <dicki...@gmail.com> added the comment:
This isn't a bug: in short, you're evaluating a discontinuous function very close to a discontinuity; the errors inherent in floating-point arithmetic put you the "wrong" side of the discontinuity. Or more simply, with binary floating-point, What You See Is Not What You Get. When you type 1.2, the value actually stored is the closest values that's exactly representable as a float, which turns out to be 1.1999999999999999555910790149937383830547332763671875. Similarly, the value actually stored for 0.2 is 0.200000000000000011102230246251565404236316680908203125. And 1.1999999999999999555910790149937383830547332763671875 % 0.200000000000000011102230246251565404236316680908203125 is 0.199999999999999900079927783735911361873149871826171875. Some references: https://docs.python.org/3/tutorial/floatingpoint.html https://docs.python.org/3/reference/expressions.html#id17 ---------- nosy: +mark.dickinson resolution: -> not a bug stage: -> resolved status: open -> closed _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue34337> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
