El domingo, 21 de julio de 2013 12:31:42 UTC+2, Steven D'Aprano escribió: > On Sun, 21 Jul 2013 03:19:24 -0700, pablobarhamalzas wrote: > > > > > Thank's for all the replies! I've tried some of the imporovements you > > > suggested (using math.exp() and sum() or math.fsum()). None of that made > > > the code faster, because they are functions you are calling lots of > > > times, and function calling is quite time expensive (same as x**(1/2) is > > > faster than math.sqrt(x)). > > > > You are *badly* mistaken. Not only is sqrt more accurate, but it is also > > much faster. > > > > > > [steve@ando ~]$ python3.3 -m timeit -s "x = 2.357e7" "x**0.5" > > 1000000 loops, best of 3: 0.319 usec per loop > > [steve@ando ~]$ python3.3 -m timeit -s "x = 2.357e7" -s "from math import > > sqrt" "sqrt(x)" > > 10000000 loops, best of 3: 0.172 usec per loop > > > > > > How exactly are you timing the code?
I'm timing the whole program with cProfile. Removing math.sqrt() from a function and using **(1/2) instead cut the execution time for a significant amount (~0.035 to ~0.020). I can't see another explanation for the speed increase... -- http://mail.python.org/mailman/listinfo/python-list
