[Numpy-discussion] Vectorizing array updates

Dan Goodman dg.gmane@thesamovar....
Wed Apr 29 16:19:32 CDT 2009


Robert Kern wrote:
> On Wed, Apr 29, 2009 at 08:03, Daniel Yarlett <daniel.yarlett@gmail.com> wrote:
> 
>> As you can see, Current is different in the two cases. Any ideas how I
>> can recreate the behavior of the iterative process in a more numpy-
>> friendly, vectorized (and hopefully quicker) way?
> 
> Use bincount().

Neat. Is there a memory efficient way of doing it if the indices are 
very large but there aren't many of them? e.g. if the indices were 
I=[10000, 20000] then bincount would create a gigantic array of 20000 
elements for just two addition operations!

Dan G.



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