Numeric vs numarray speed

[Fernando Pérez]

Nick B wrote:

> Hi any Numeric users,
> 
> I have some image processing code that runs fine under Py2.1 and Py2.2 with
> Numeric.  Trying the same thing under the upcoming successor numarray (just
> global find-and-replace numarray for Numeric in my code) it runs, but way
> slower than 1/10 the speed.  So for now I'm sticking to Numeric.
> 
> Anyone any ideas why.  Is numarray full of debug code ?

b/c Numarray is trying to solve the performance issues which Numeric has with 
_huge_ arrays. The tradeoff is that right now, the small array case is much 
worse in Numarray than in Numeric. But the developers are perfectly aware of 
this case, and befor numarray is officially released, they'll bring the 
performance back to par for small arrays.

It's just that right now they are concentrating on the architecture and design 
issues, no optimizations have been done yet. It would be good if you could 
keep your test code around, and as numarray begins to get closer to public 
release, run it again. If you still see a performance difference, by all 
means report it to the dev team, as I'm sure they'll be interested. It's 
possible that your code stresses numarray in a way they haven't foreseen and 
uncovers particularly problematic corner cases.

Cheers,

f.