[Numpy-discussion] [OT] Starving CPUs article featured in IEEE's ComputingNow portal

Pauli Virtanen pav at iki.fi
Sat Mar 20 13:26:21 EDT 2010

Anne Archibald wrote:
> I'm not knocking numpy; it does (almost) the best it can. (I'm not
> sure of the optimality of the order in which ufuncs are executed; I
> think some optimizations there are possible.)

Ufuncs and reductions are not performed in a cache-optimal fashion, IIRC dimensions are always traversed in order from left to right. Large speedups are possible in some cases, but in a quick try I didn't manage to come up with an algorithm that would always improve the speed (there was a thread about this last year or so, and there's a ticket). Things varied between computers, so this probably depends a lot on the actual cache arrangement.

But perhaps numexpr has such heuristics, and we could steal them?

Pauli Virtanen

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