[Numpy-discussion] [Repost] Adding the arrays returned in an array iterator
Thu Jun 2 20:36:33 CDT 2011
Bumping my question tentatively. I am fairly sure there is a good answer and
for some reason it got overlooked.
---------- Forwarded message ----------
From: srean <email@example.com>
Date: Fri, May 27, 2011 at 10:36 AM
Subject: Adding the arrays in an array iterator
To: Discussion of Numerical Python <firstname.lastname@example.org>
I have to sum up an unknown number of ndarrays of the same size. These
arrays, possibly thousands in number, are provided via an iterator. Right
now I use python reduce with operator.add.
Does that invoke the corresponding ufunc internally ? I want to avoid
creating temporaries, which I suspect a naive invocation of reduce will
create. With ufunc I know how to avoid making copies using the output
parameter, but not sure how to make use of that in reduce.
It is not essential that I use reduce though, so I would welcome idiomatic
and efficient way of executing this. So far I have stayed away from building
an ndarray object and summing across the relevant dimension. Is that what I
should be doing ? Different invocations of this function has different
number of arrays, so I cannot pre-compile away this into a numexpr.
Thanks and regards
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