On Fri, Oct 21, 2016 at 1:45 AM, Sebastian Berg <sebast...@sipsolutions.net> wrote:
> On Do, 2016-10-20 at 21:38 -0600, Charles R Harris wrote: > > > > > > On Thu, Oct 20, 2016 at 9:11 PM, Nathaniel Smith <n...@pobox.com> > > wrote: > > > On Thu, Oct 20, 2016 at 7:58 PM, Charles R Harris > > > <charlesr.har...@gmail.com> wrote: > > > > Hi All, > > > > > > > > I've put up a preliminary PR for the proposed fpower ufunc. Apart > > > from > > > > adding more tests and documentation, I'd like to settle a few > > > other things. > > > > The first is the name, two names have been proposed and we should > > > settle on > > > > one > > > > > > > > fpower (short) > > > > float_power (obvious) > > > > > > +0.6 for float_power > > > > > > > The second thing is the minimum precision. In the preliminary > > > version I have > > > > used float32, but perhaps it makes more sense for the intended > > > use to make > > > > the minimum precision float64 instead. > > > > > > Can you elaborate on what you're thinking? I guess this is because > > > float32 has limited range compared to float64, so is more likely to > > > see overflow? float32 still goes up to 10**38 which is < > > > int64_max**2, > > > FWIW. Or maybe there's some subtlety with the int->float casting > > > here? > > logical, (u)int8, (u)int16, and float16 get converted to float32, > > which is probably sufficient to avoid overflow and such. My thought > > was that float32 is something of a "specialized" type these days, > > while float64 is the standard floating point precision for everyday > > computation. > > > > > Isn't the behaviour we already have (e.g. such as mean). > > ints -> float64 > inexacts do not get upcast? > > Hmm... The best way to do that would be to put the function in `fromnumeric` and do it in python rather than as a ufunc, then for integer types call power with `dtype=float64`. I like that idea better than the current implementation, my mind was stuck in the ufunc universe. Chuck
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