Tim, sorry for I send it to you personally, I was abused by thunderbird. Tim N. van der Leeuw a écrit :
> > Your C++ version got me the following timings (using gcc 3.4.5 as the > compiler, MinGW version, with -O6): > > ... > > > Hmmm... Can we conclude now that carefully crafted C++ code is about > twice as fast as casually and intuitively written Python code? ;) (Just > kidding here of course) Every C++ code must be carefully crafted :). But your benchmark surprise me, here is what I get on my windows box : Python2.4 : =========== [EMAIL PROTECTED] /cygdrive/c/Documents and Settings/maric/Bureau $ which python2.4 /usr/bin/python2.4 [EMAIL PROTECTED] /cygdrive/c/Documents and Settings/maric/Bureau $ which python /cygdrive/c/Python24/python [EMAIL PROTECTED] /cygdrive/c/Documents and Settings/maric/Bureau $ python2.4 testpython.py so long... What do you know fool chicken crosses road Elapsed: 3.655000 seconds [EMAIL PROTECTED] /cygdrive/c/Documents and Settings/maric/Bureau $ python testpython.py so long... What do you know fool chicken crosses road Elapsed: 3.077764 seconds Cygwin version is slower, but not too much. C++, compiled with VS2005, release, no other configuration : ============================================================ print_occurence_of_strings What do you know? chicken crosses road fool so long... print_occurence_of_unique_strings What do you know? chicken crosses road fool so long... print_occurence_of_unique_strings_compared_by_address What do you know? chicken crosses road fool so long... strings : 16.718 # memory allocation is quite bad unique strings : 1.188 compared by address : 0.453 C++, with gcc 3.3/Cygwin ======================== [EMAIL PROTECTED] /cygdrive/c/Documents and Settings/maric/Bureau $ g++ -O3 -o testcpp testcpp.cpp [EMAIL PROTECTED] /cygdrive/c/Documents and Settings/maric/Bureau $ ./testcpp print_occurence_of_strings What do you know? chicken crosses road fool so long... print_occurence_of_unique_strings What do you know? chicken crosses road fool so long... print_occurence_of_unique_strings_compared_by_address What do you know? chicken crosses road fool so long... strings : 17.266 # still bad unique strings : 1.547 compared by address : 0.375 Hum, with my old gcc I get equal or better performances than with VS2005. Finally, the equivalent code is still about 10x faster in c++ than in Python, as it was on my Linux box. Mc Osten a écrit : ... > However, I would have written the code using a proper compare function > rather than using two sets. In this particular case the number of > elements of the first set is negligible in respect of the initial vector > size, thus copying it again does not take a lot of time. > But such code is optimized for the problem itself: in the real world I Of course, it's a quick hack to get the same behavior. > suppose we would have passed set a proper comparison function that > checks address and then string equality. > Yes, furthermore, that is *exactly* what the python code is doing (see my other post to Fredrik). -- _____________ Maric Michaud _____________ Aristote - www.aristote.info 3 place des tapis 69004 Lyon Tel: +33 426 880 097 -- http://mail.python.org/mailman/listinfo/python-list
