On Feb 18, 2014 11:55 AM, "Robert Kern" <robert.k...@gmail.com> wrote: > > On Tue, Feb 18, 2014 at 9:51 AM, Sturla Molden <sturla.mol...@gmail.com> wrote: > > Charles R Harris <charlesr.har...@gmail.com> wrote: > >> This is apropos issue #899 <<a > >> href="https://github.com/numpy/numpy/issues/899";> https://github.com/numpy/numpy/issues/899</a>>, > >> where it is suggested that power promote integers to float. That sounds > >> reasonable to me, but such a change in behavior makes it a bit iffy. > >> > >> Thoughts? > > > > Numpy should do the same as Python does. > > That's problematic because Python's behavior is value dependent. > > Python 3.3.1 (default, May 16 2013, 17:20:13) > [GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))] on darwin > Type "help", "copyright", "credits" or "license" for more information. > >>> 2 ** 2 > 4 > >>> 2 ** -2 > 0.25 > > That's fine if you only have one value for each operand. When you have > multiple values for each operand, say an exponent array containing > both positive and negative integers, that becomes a problem. > Generally, we try to make ufuncs return types that are predictable > from the types of the operands, not the values of the operands. > > I am -1 on the proposal to make power(x:int, y:int) always return a > float. It is usually trivial to just make the exponent a float if one > wants a float returned. Or we could introduce an fpow() that always > coerces the inputs to the best inexact type.
What about making it floats for int types but int for uint types?
_______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
