[Numpy-discussion] String sort
Francesc Altet
faltet@carabos....
Sat Feb 9 15:29:07 CST 2008
Chuck,
One more thing on this. I've been doing some benchmarking with my
opt_memcpy() macro in the quicksort_string function, and I should say
that while it is definitely more efficient than my system memcpy for
small values of n (the number of bytes to copy), this doesn't keep true
for all values of n. For example, for n<16, opt_memcpy() can be more
than 4x faster than system memcpy (and this is why I naively thought
that it would be faster in general). However, for n>80, memcpy beats
opt_memcpy between a 25% and 100% (depending on whether n is divisible
by 2, 4 or 8). This is on my Linux system (Ubuntu 7.10), but perhaps
with Windows the behaviour can be different.
I think I would be able to come up with a routine that can offer a
balance between opt_memcpy and system memcpy, but that should take some
time. So, until I (or anybody else) do more research on this, I think
it would be safer if you use system memcpy for string sorting in NumPy.
Cheers,
--
>0,0< Francesc Altet http://www.carabos.com/
V V Cárabos Coop. V. Enjoy Data
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