[Numpy-discussion] python numpy code many times slower than c++

Wes McKinney wesmckinn at gmail.com
Thu Jan 22 18:09:05 EST 2009


Windows XP, Pentium D, Python 2.5.2

On Thu, Jan 22, 2009 at 6:03 PM, Robert Kern <robert.kern at gmail.com> wrote:

> On Thu, Jan 22, 2009 at 17:00, Wes McKinney <wesmckinn at gmail.com> wrote:
> > import cProfile
> >
> > def f():
> >     pass
> >
> > def g():
> >     for i in xrange(1000000):
> >         f()
> >
> > cProfile.run("g()")
> >
> >>test.py
> >          1000003 function calls in 1.225 CPU seconds
> >
> >    Ordered by: standard name
> >
> >    ncalls  tottime  percall  cumtime  percall filename:lineno(function)
> >         1    0.000    0.000    1.225    1.225 <string>:1(<module>)
> >   1000000    0.464    0.000    0.464    0.000 test.py:3(f)
> >         1    0.761    0.761    1.225    1.225 test.py:6(g)
> >         1    0.000    0.000    0.000    0.000 {method 'disable' of
> > '_lsprof.Profiler' objects}
> >
> > Running this with line_profiler:
> >
> > Timer unit: 2.9485e-010 s
> >
> > File: test.py
> > Function: g at line 9
> > Total time: 0.855075 s
> >
> > Line #      Hits         Time  Per Hit   % Time  Line Contents
> > ==============================================================
> >      9                                           @profiler
> >     10                                           def g():
> >     11   1000001   1844697930   1844.7     63.6         for i in
> > xrange(1000000):
> >     12   1000000   1055333053   1055.3     36.4                 f()
> >
> > Which is what I would expect. Hmm
>
> What platform are you on?
>
> --
> Robert Kern
>
> "I have come to believe that the whole world is an enigma, a harmless
> enigma that is made terrible by our own mad attempt to interpret it as
> though it had an underlying truth."
>  -- Umberto Eco
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>
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