[Numpy-discussion] Integers to negative integer powers, time for a decision.

Nathaniel Smith njs at pobox.com
Sat Oct 8 06:40:50 EDT 2016


On Fri, Oct 7, 2016 at 6:12 PM, Charles R Harris
<charlesr.harris at gmail.com> wrote:
> Hi All,
>
> The time for NumPy 1.12.0 approaches and I like to have a final decision on
> the treatment of integers to negative integer powers with the `**` operator.
> The two alternatives looked to be
>
> Raise an error for arrays and numpy scalars, including 1 and -1 to negative
> powers.
>
> Pluses
>
> Backward compatible
> Allows common powers to be integer, e.g., arange(3)**2
> Consistent with inplace operators
> Fixes current wrong behavior.
> Preserves type
>
>
> Minuses
>
> Integer overflow
> Computational inconvenience
> Inconsistent with Python integers
>
>
> Always return a float
>
> Pluses
>
> Computational convenience
>
>
> Minuses
>
> Loss of type
> Possible backward incompatibilities
> Not applicable to inplace operators

I guess I could be wrong, but I think the backwards incompatibilities
are going to be *way* too severe to make option 2 possible in
practice.

-n

-- 
Nathaniel J. Smith -- https://vorpus.org



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