On Fri, Sep 13, 2019 at 2:59 PM Philip Hodge <ho...@stsci.edu> wrote: > > On 9/13/19 8:45 AM, Irvin Probst wrote: > > On 13/09/2019 14:05, Philip Hodge wrote: > >> > >> Isn't that just for consistency with Python 3 round()? I agree that > >> the discrepancy with np.set_printoptions is not necessarily expected, > >> except possibly for backwards compatibility. > >> > >> > > > > I've just checked and np.set_printoptions behaves as python's round: > > > > >>> round(16.055,2) > > 16.05 > > >>> np.round(16.055,2) > > 16.06 > > > > I don't know why round and np.round do not behave the same, actually I > > would even dare to say that I don't care :-) > > However np.round and np.set_printoptions should provide the same > > output, shouldn't they ? This discrepancy is really disturbing whereas > > consistency with python's round looks like the icing on the cake but > > in no way a required feature. > > > > Python round() is supposed to round to the nearest even value, if the > two closest values are equally close. So round(16.055, 2) returning > 16.05 was a surprise to me. I checked the documentation and found a > note that explained that this was because "most decimal fractions can't > be represented exactly as a float." round(16.55) returns 16.6. > > Phil > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion
Ah, of course, endless double-precision shenanigans... >>> format(16.055, '.30f') '16.054999999999999715782905695960' >>> format(16.55, '.30f') '16.550000000000000710542735760100' András _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@python.org https://mail.python.org/mailman/listinfo/numpy-discussion
