[Numpy-discussion] Speeding up numarray -- questions on its design

Travis Oliphant oliphant at ee.byu.edu
Tue Jan 18 14:26:32 CST 2005


Paul Dubois wrote:

> I haven't followed this discussion in detail but with respect to space 
> for 'descriptors', it would simply be foolish to malloc space for 
> these. The cost is ridiculous. You simply have to decide how big a 
> number of dimensions to allow, make it a clearly findable definition 
> in the sources, and dimension everything that big.
>
Thanks for this comment.   I can see now that it makes sense as it would 
presumably speed up small array creation.   Why was this not done in the 
original sources?

> Originally when we discussed this we considered 7, since that had been 
> (and for all I know still is) the maximum array dimension in Fortran. 
> But Jim Huginin needed 11 or something like it for his imaging. I've 
> seen 40 in the numarray sources I think.

>
> It seems to me that an application that would care about this space 
> (it being, after all, per array object) would be unusual indeed.
>
> If I've misunderstood what you're talking about, never mind. (:->


I think you've understood this part of it and have given good advice.

>
> My advice is to make flexibility secondary to performance. It is 
> always possible to layer on flexibility for those who want it.


I like this attitude.

-Travis





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