[Development] submitting a multi-dimensional container class for Qt: QNDArray

Glen Mabey gmabey at swri.org
Fri Jan 11 14:19:19 CET 2013


On Jan 11, 2013, at 1:56 AM, Uwe Rathmann wrote:

> On Wed, 09 Jan 2013 16:02:17 -0600, Thiago Macieira wrote:
> 
>>>> I think this is out of the scope of Qt. I  do not see that many uses
>>>> case for normal Qt applications.
>>> 
>>> I am not surprised that some developers would feel this way, and I
>>> think I would also feel that way if Qt were still strictly a GUI
>>> toolkit, instead of the application framework that it became in Qt4.
>> 
>> I'm not sure it's out of scope for Qt. In fact, I don't know yet whether
>> it should be part of Qt Core or not.
> 
> Something I was missing several times is a 2D container. Qt has objects 
> organized in rows and columns ( QTable, QImage ... ) - so IMHO it is 
> related to Qt.
> 
> But I would expect to find a class with an API comparable to QVector.

Yes, if the container object is strictly 2D, then I think that the API would probably be much like that of QVector.

There are cases I've used where the DTYPE is a non-numeric class, but most of the time (for me) it's been numeric, and the ability to do basic mathematical operations (such as add 2 of them together, or multiply all elements by a scalar) is a really handy feature.

Where it starts to get tricky is what the behavior should be when two instances of different dimensionality are multiplied (for example), and that is precisely what Numpy has already hammered out (they call it "broadcasting"), and I sure didn't want to reinvent the wheel there!

Best Regards,
Glen


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