[Numpy-discussion] Integers to integer powers, let's make a decision

[Charles R Harris]

On Mon, Jun 6, 2016 at 2:11 PM, Marten van Kerkwijk <
m.h.vankerkwijk at gmail.com> wrote:

> Hi Chuck,
>
> I consider either proposal an improvement, but among the two I favour
> returning float for `**`, because, like for `/`, it ensures one gets
> closest to the (mathematically) true answer in most cases, and makes
> duck-typing that much easier -- I'd like to be able to do x** y without
> having to worry whether x and y are python scalars or numpy arrays of
> certain type.
>
> I do agree with Nathaniel that it would be good to check what actually
> breaks. Certainly, if anybody is up to making a PR that implements either
> suggestion, I'd gladly check whether it breaks anything in astropy.
>
> I  should add that I have no idea how to assuage the fear that new code
> would break with old versions of numpy, but on the other hand, I don't know
> its vailidity either, as it seems one either develops larger projects  for
> multiple versions and tests, or writes more scripty things for whatever the
> current versions are. Certainly, by this argument I better not start using
> the new `@` operator!
>
> I do think the argument that for division it was easier because there was
> `//` already available is a red herring: here one can use `np.power(a, b,
> dtype=...)` if one really needs to.
>

It looks to me like users want floats, while developers want the easy path
of raising an error. Darn those users, they just make life sooo difficult...

Chuck
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