[Numpy-discussion] ufunc oddities

Robert Kern robert.kern@gmail....
Sat May 24 22:18:18 CDT 2008


On Sat, May 24, 2008 at 10:12 PM, Charles R Harris
<charlesr.harris@gmail.com> wrote:
>
> On Sat, May 24, 2008 at 9:06 PM, Robert Kern <robert.kern@gmail.com> wrote:
>>
>> On Sat, May 24, 2008 at 10:02 PM, Charles R Harris
>> <charlesr.harris@gmail.com> wrote:
>> > So what about the rule that the array type takes precedence over the
>> > scalar
>> > type? That is broken for booleans.
>>
>> Yes, and if it wasn't an intentional special case (I don't recall
>> discussing it on the list, but it might have been), then it's a bug
>> and suitable for changing. The other behaviors are intentional and
>> thus not suitable for changing.
>
> So how do we know which is which? How does one write a test for an
> unspecified behavior? And it is clear that add.reduce breaks the rules for
> booleans.

It breaks it for every integer type, in fact.

In [11]: add.reduce(array([1]*257, dtype=uint8))
Out[11]: 257

I thought we only did the accumulator-dtype changing for the .sum()
method, but I was wrong.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
 -- Umberto Eco


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