[Numpy-discussion] suggestion for generalizing numpy functions

[Darren Dale]

On Mon, Jul 13, 2009 at 7:12 PM, Darren Dale <dsdale24 at gmail.com> wrote:

> 2009/7/13 Stéfan van der Walt <stefan at sun.ac.za>
>
>> Hi Darren
>>
>> 2009/7/13 Darren Dale <dsdale24 at gmail.com>:
>> > I've put together a first cut at implementing __array_prepare__, which
>> > appears to work, and I would like to request feedback. Here is an
>> overview
>> > of the approach:
>>
>> This is pretty neat!  Do you have a quick snippet at hand illustrating its
>> use?
>
>
> That would be helpful, wouldn't it? The attached script is a modified
> version of RealisticInfoArray from
> http://docs.scipy.org/doc/numpy/user/basics.subclassing.html . It should
> yield the following output:
>
>
> starting with [0 1 2 3 4]
> which is of type <class '__main__.MyArray'>
> and has info attribute = "information"
> subtracting 3 from [0 1 2 3 4]
> subtract calling __array_prepare__ on [0 1 2 3 4] input
> output array is now of type <class '__main__.MyArray'>
> output array values are still uninitialized:
>         [139911601789568        39578752 139911614885536        39254560
>               48]
> __array_prepare__ is updating info attribute on output
> __array_prepare__ finished, subtract ufunc is taking over
> subtract calling __array_wrap__ on [0 1 2 3 4] input
> output array has initial value: [-3 -2 -1  0  1]
> __array_wrap__ is setting output endpoints to 0
> yielding [ 0 -2 -1  0  0]
> which is of type <class '__main__.MyArray'>
> and has info attribute = "new_information"
>

This is a gentle ping, hoping to get some feedback so this feature has a
chance of being included in the next release.

Darren
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