[Numpy-tickets] [NumPy] #594: Major slowdown when mixing array with Python's list
NumPy
numpy-tickets@scipy....
Sat Oct 20 08:57:29 CDT 2007
#594: Major slowdown when mixing array with Python's list
------------------------+---------------------------------------------------
Reporter: Boris | Owner: somebody
Type: defect | Status: new
Priority: normal | Milestone:
Component: numpy.core | Version: 1.0.2
Severity: normal | Keywords:
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I encountered a major slowdown every time I use a simple Python list with
an array function. Here is an example which occurs quite often in my code:
{{{
t1 = Timer(setup='from numpy import *; x=arange(1,100);
k=array([97,43,3,6,23,0])', stmt='x[k]')
t1.timeit(10000)
=0.029493949996
t2 = Timer(setup='from numpy import *; x=arange(1,100);
k=[97,43,3,6,23,0]', stmt='x[k]')
t2.timeit(10000)
=0.177627355842
}}}
I would expect that t2 is as fast as t1.
Using an array instead of the list is also no option since I create this
index lists very often and
{{{
k=[97,43,3,6,23,0]
}}}
is a lot faster than
{{{
k=array([97,43,3,6,23,0])
}}}
This slowdown also occurs with other functions, e.g. sum, sort.
--
Ticket URL: <http://scipy.org/scipy/numpy/ticket/594>
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