[Numpy-discussion] product of arrays of different lengths

Alan G Isaac aisaac@american....
Mon Sep 15 08:08:20 CDT 2008


On 9/15/2008 6:25 AM Francesc Alted apparently wrote:
> max_idx = min(len(A), len(B))
> (A[:max_idx] * B[:max_idx]).sum()
> 
> which does not require a copy becuase the [:max_idx] operator returns 
> just a view of the arrays.

But it still requires creating a new array,
so perhaps use of ``dot`` above or even::

	sum(ai*bi for ai,bi in izip(A,B))

is worth considering in this case.
(That is the built-in ``sum``.)

Alan Isaac



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