[Numpy-discussion] Slow performance in array protocol with string arrays

Warren Focke focke at slac.stanford.edu
Wed Jan 4 14:33:20 CST 2006


I ran up against the dimesion limit in Numeric back when it was 10.  Or
20, it was actually defined inconsistently in different places, and you
could crash the interpreter by creating and array w/ >10 dim in a part
of the code that would let you do that and feeding it to a part that
wouldn't.  I didn't complain about the limit because the code I was
working on was a toy^H^H^Hlearning exercise and I didn't complain about
the inconsistency because I suck.

I was trying to make an FFT routine that would reshape the input sequence
to have one dimension per prime factor of its length, and then manipulate
that.

Warren Focke

On Wed, 4 Jan 2006, Francesc Altet wrote:

> A Dimecres 04 Gener 2006 18:27, Christopher Barker va escriure:
> > > Francesc Altet wrote:
> > >> It seems that numarray implementation for the array protocol in string
> > >> arrays is very slow for dimensionality > 10:
> >
> > OK, I'll bite -- what in the world do you need an array of strings with
> > dimensionality > 10 for ?
>
> Good question. The fact is that Numeric, numarray and scipy_core has
> all been designed to support objects up to 32 (and perhaps 40 in some
> cases) dimensions. Why? I must confess that I don't exactly know, but
> when your mission is to check every bit of the implementation and push
> your package to its limits, you may encounter very funny things that
> probably will never be a problem for real users.
>
> Somehow, this kind of issues with high dimensionalities are sometimes
> useful for isolating other potential problems. So, yeah, one can say
> that they are usally a loss of time, but sometimes they can save your
> life (well, kind of ;-).
>
> --
> >0,0<   Francesc Altet     http://www.carabos.com/
> V   V   Cárabos Coop. V.   Enjoy Data
>  "-"
>
>
>
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