[Numpy-discussion] improving arraysetops
Neil Crighton
neilcrighton at gmail.com
Sun Jun 14 18:40:50 EDT 2009
Robert Cimrman <cimrman3 <at> ntc.zcu.cz> writes:
>
> Hi,
>
> I am starting a new thread, so that it reaches the interested people.
> Let us discuss improvements to arraysetops (array set operations) at [1]
> (allowing non-unique arrays as function arguments, better naming
> conventions and documentation).
>
> r.
>
> [1] http://projects.scipy.org/numpy/ticket/1133
>
Hi,
These changes looks good to me. For point (1) I think we should fold the
unique and _nu code into a single function. For point (3) I like in1d - it's
shorter than isin1d but is still clear.
What about merging unique and unique1d? They're essentially identical for an
array input, but unique uses the builtin set() for non-array inputs and so is
around 2x faster in this case - see below. Is it worth accepting a speed
regression for unique to get rid of the function duplication? (Or can they be
combined?)
Neil
In [24]: l = list(np.random.randint(100, size=10000))
In [25]: %timeit np.unique1d(l)
1000 loops, best of 3: 1.9 ms per loop
In [26]: %timeit np.unique(l)
1000 loops, best of 3: 793 µs per loop
In [27]: l = list(np.random.randint(100, size=1000000))
In [28]: %timeit np.unique(l)
10 loops, best of 3: 78 ms per loop
In [29]: %timeit np.unique1d(l)
10 loops, best of 3: 233 ms per loop
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