[Numpy-discussion] Broadcasting question

Olivier Grisel olivier.grisel@ensta....
Thu Dec 4 10:53:36 CST 2008


2008/12/4 Stéfan van der Walt <stefan@sun.ac.za>:
> Hi Olivier
>
> 2008/12/4 Olivier Grisel <olivier.grisel@ensta.org>:
>> To avoid the python level loop I then tried to use broadcasting as follows:
>>
>>>>> c = sum((a[:,newaxis,:] - b) ** 2, axis=2)
>>
>> But this build a useless and huge (d1, d2, d3) temporary array that
>> does not fit in memory for large values of d1, d2 and d3...
>
> Does  numpy.lib.broadcast_arrays do what you need?

That looks exactly what I am looking for. Apparently this is new in
1.2 since I cannot find it in the 1.1 version of my system.

Thanks,

-- 
Olivier


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