[Numpy-discussion] extracting a random subset of a vector
Curzio Basso
curzio.basso at unibas.ch
Tue Aug 31 06:04:00 CDT 2004
Hi all, I have an optimization problem.
I currently use the following code to select a random subset of a rank-1
array:
----------------------------------------------------------
import numarray as NA
import numarray.random_array as RA
N = 1000
M = 100
full = NA.arange(N)
subset = full[RA.permutation(N)][:M]
---------------------------------------------------------
However, it's quite slow (at least with N~40k), and from the hotshot
output is looks like it's the indexing, not the permutation, which takes
time.
Does anyone have a suggestion on a faster pure-python implementation?
thanks
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