On Thu, Oct 2, 2014 at 10:12 PM, Charles R Harris <charlesr.har...@gmail.com > wrote:
> > > On Thu, Oct 2, 2014 at 9:29 PM, Nathaniel Smith <n...@pobox.com> wrote: > >> On Fri, Oct 3, 2014 at 3:20 AM, Charles R Harris >> <charlesr.har...@gmail.com> wrote: >> > >> > On Thu, Oct 2, 2014 at 7:06 PM, Benjamin Root <ben.r...@ou.edu> wrote: >> >> >> >> Out[1] has an integer divided by an integer, and you can't represent >> nan >> >> as an integer. Perhaps something weird was happening with type >> promotion >> >> between versions? >> > >> > >> > Also note that in python3 the '/' operator does float rather than >> integer >> > division. >> > >> >>>> np.array(0) / np.array(0) >> > __main__:1: RuntimeWarning: invalid value encountered in true_divide >> > nan >> >> Floor division still acts the same though: >> >> >>> np.array(0) // np.array(0) >> __main__:1: RuntimeWarning: divide by zero encountered in floor_divide >> 0 >> >> The seterr warning system makes a lot of sense for IEEE754 floats, >> which are specifically designed so that 0/0 has a unique well-defined >> answer. For ints though this seems really broken to me. 0 / 0 = 0 is >> just the wrong answer. It would be nice if we had something reasonable >> to return, but we don't, and I'd rather raise an error than return the >> wrong answer. >> > > That's an option, although arguable for arrays of numbers. However, the > fact that we don't know *which* numbers caused the problem strengthens the > argument for an error. > > Plus the g*dawful warning default to only warn once. That has always bothered me, it just seems useless. Chuck
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