[Numpy-discussion] distance_matrix: how to speed up?
Vincent Schut
schut@sarvision...
Thu May 22 02:45:32 CDT 2008
Emanuele Olivetti wrote:
<snip>
>
> This solution is super-fast, stable and use little memory.
> It is based on the fact that:
> (x-y)^2*w = x*x*w - 2*x*y*w + y*y*w
>
> For size1=size2=dimensions=1000 requires ~0.6sec. to compute
> on my dual core duo. It is 2 order of magnitude faster than my
> previous solution, but 1-2 order of magnitude slower than using
> C with weave.inline.
>
> Definitely good enough for me.
>
>
> Emanuele
Reading this thread, I remembered having tried scipy's sandbox.rbf
(radial basis function) to interpolate a pretty large, multidimensional
dataset, to fill in the missing data points. This however failed soon
with out-of-memory errors, which, if I remember correctly, came from the
pretty straightforward distance calculation between the different data
points that is used in this package. Being no math wonder, I assumed
that there simply was no simple way to calculate distances without using
much memory, and ended my rbf experiments.
To make a story short: correct me if I am wrong, but might it be an idea
to use the above solution in scipy.sandbox.rbf?
Vincent.
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