[Numpy-discussion] Performance problems with strided arrays in NumPy

Travis Oliphant oliphant at ee.byu.edu
Fri Apr 14 16:04:02 CDT 2006


faltet at xot.carabos.com wrote:

>Hi,
>
>I'm seeing some slowness in NumPy when dealing with strided arrays.
>numarray is dealing better with these situations, so I guess that
>something could be done in NumPy about this. Below are the situations
>that I've found up to now (maybe there are others). For the timings,
>I've used numpy 0.9.7.2278 and numarray 1.5.1.
>  
>

What I've found in experiments like this in the past is that numarray is 
good at striding in one direction but much worse at striding in another 
direction for multi-dimensional arrays.   Of course my experiments were 
not complete.  That just seemed to be the case.

The array-iterator construct handles almost all of these cases.   The 
copy method is a good place to start since it uses that code.

-Travis





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