[Tutor] finding square roots

Alan Gauld alan.gauld at btinternet.com
Sat Oct 6 00:55:48 CEST 2007

"Eric Brunson" <brunson at brunson.com> wrote

>>>>>> t = timeit.Timer( "sqrt(12)", "from math import sqrt" )
>>>>>> print t.timeit(10000000)
>>> 7.17679214478

>>>>> timeit.Timer("import math; math.sqrt(64)").timeit(1000)
>> 0.002298138362618829
>>>>> timeit.Timer("import math; 64 ** 0.5").timeit(1000)
>> 0.018225722100503106
>> I get the opposite result by includsing the importt in both
>> timing sessions. Looks like it was the import that was slow.
> Maybe I'm mis-remembering the documentation of timeit.  I thought 
> the
> second argument to the Timer constructor was "setup code", i.e. code 
> to
> be executed once before executing the first argument in the timing 
> loop.

It seems to suggest that, so I don't understand the reason,
but in any case its a fairer comparison to include the import in both 
Doing it your way gives me:

>>> timeit.Timer("64 ** 0.5", "import math").timeit(1000)
>>> timeit.Timer("math.sqrt(64)", "import math").timeit(1000)

Which favours ** but by a smaller margin.


Alan Gauld
Author of the Learn to Program web site

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