On Mon, Jun 13, 2016 at 12:07 PM, <josef.p...@gmail.com> wrote:
>
>
> On Mon, Jun 13, 2016 at 11:51 AM, <josef.p...@gmail.com> wrote:
>
>>
>>
>> On Mon, Jun 13, 2016 at 11:25 AM, Antoine Pitrou <solip...@pitrou.net>
>> wrote:
>>
>>> On Mon, 13 Jun 2016 10:49:44 -0400
>>> josef.p...@gmail.com wrote:
>>> >
>>> > My argument is that `**` is like integer division and sqrt where the
>>> domain
>>> > where integer return are the correct numbers is too small to avoid
>>> > headaches by users.
>>>
>>> float64 has less integer precision than int64:
>>>
>>> >>> math.pow(3, 39) == 3**39
>>> False
>>> >>> np.int64(3)**39 == 3**39
>>> True
>>>
>>
>> but if a user does this, then ??? (headaches or head scratching)
>>
>> >>> np.array([3])**39
>> RuntimeWarning: invalid value encountered in power
>>
>> array([-2147483648], dtype=int32)
>>
>
> I forgot to add
>
> the real headaches start in the second call, when we don't get the
> RuntimeWarning anymore
>
> >>> np.array([4])**39
> array([-2147483648], dtype=int32)
>
>
> ("Now, why do I owe so much money, when I made a huge profit all year." )
>
(grumpy off-topic complaint:
The Canadian tax system is like this. They make a mistake in transferring
information to a new computerized system, and then they send a bill for
taxes based on reassessment of something that happened 5 years ago because
their computerized record is wrong.
)
>
> Josef
>
>
>
>>
>> Josef
>>
>>
>>>
>>>
>>> (as a sidenote, np.float64's equality operator seems to be slightly
>>> broken:
>>>
>>> >>> np.float64(3)**39 == 3**39
>>> True
>>> >>> int(np.float64(3)**39) == 3**39
>>> False
>>> >>> float(np.float64(3)**39) == 3**39
>>> False
>>> )
>>>
>>> Regards
>>>
>>> Antoine.
>>>
>>>
>>> _______________________________________________
>>> NumPy-Discussion mailing list
>>> NumPy-Discussion@scipy.org
>>> https://mail.scipy.org/mailman/listinfo/numpy-discussion
>>>
>>
>>
>
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