[SciPy-User] Subclassing scipy sparse matrix class

[Aronne Merrelli]

On Fri, Dec 2, 2011 at 8:39 AM, Bruce Southey <bsouthey at gmail.com> wrote:

> **
> On 12/01/2011 04:36 PM, Aronne Merrelli wrote:
>
>
> On Wed, Nov 30, 2011 at 3:01 AM, Per Nielsen <evilper at gmail.com> wrote:
>
>> Hi all
>>
>>  I am trying to create a subclass of the sparse matrix class in scipy,
>> to add some extra methods I need.
>>
>>  I have tried to follow the guide on: http://www.scipy.org/Subclasses but
>> without much luck, the view method does not exist for the sparse matrix
>> class. Below is a script I have created
>>
>>
> Hi,
>
> It appears that sparse matrices do not inherit from numpy.ndarray:
>
>
> Surely you did notice that sparse is part of scipy not numpy or even the
> c++ usage when looking at the code? :-)
> As far as I know (which is not much) scipy.sparse is essentially
> self-contained in scipy/sparse directory. So you are better off just
> working with those files directly.
>
>
Well, not exactly - it looks the actual values and indices defining the
sparse matrix are stored inside numpy ndarrays in separate object
attributes, even though the sparse matrix itself is just a "plain" python
object. So it is not quite "self-contained". I'm sure there are good
reasons for implementing it that way, but it isn't obvious without knowing
those reasons why it couldn't be a direct subclass of ndarray.


Aronne
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