[Numpy-discussion] Bitwise operations and unsigned types

Charles R Harris charlesr.harris@gmail....
Fri Apr 6 01:01:34 CDT 2012


On Thu, Apr 5, 2012 at 11:57 PM, Travis Oliphant <travis@continuum.io>wrote:

> As of 1.5.1 this worked:
>
> >>> numpy.__version__
> 1.5.1
> >>> numpy.uint64(5) & 3
> 1L
>
>
> So, this is a regression and a bug.   It should be fixed so that it
> doesn't raise an error.  I believe the scalars were special cased so that a
> raw 3 would not be interpreted as a signed int when it is clearly unsigned.
>      The casting rules were well established over a long period.  They had
> issues, but they should not have been changed like this in a 1.X release.
>
> Fortunately there are work-arounds and these issues arise only in corner
> cases, but we should strive to do better.
>
>
I disagree, promoting to object kind of destroys the whole idea of bitwise
operations. I think we *fixed* a bug.

Chuck

>
>
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