outer operator then flatten numpy

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outer operator then flatten numpy



Given two numpy arrays with dimensions (a,b) and (a,c) I would like to perform an outer operation (eg. add) flattened down to an array of shape (a,b*c).


a


b


a


c


a


b*c



I can do this using reshape:


reshape


# Input arrays:
array1 = np.arange(6).reshape(2,3)
array2 = np.arange(8).reshape(2,4)

output = (array1[:,None,:] + array2[...,None]).reshape(2,-1)



While this works, I was wondering if a solution not involving explicit reshaping exists? That is, do I have to do the intermediate step as an (a,b,c)-shaped array?


a


b


c





Reshaping is virtually free. That can't be the bottleneck.
– Divakar
4 hours ago





@Divakar True, this isn't a computational bottleneck. It just seems like something which could be solved in a nicer way
– M.T
3 hours ago









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