On 1 March 2012 16:23, Andy Ray Terrel <[email protected]> wrote: > > > On Thu, Mar 1, 2012 at 9:59 AM, Marco Morandini <[email protected]> > wrote: >> >> On 03/01/2012 04:51 PM, Andy Ray Terrel wrote: >>> >>> On Thu, Mar 1, 2012 at 2:22 AM, Marco >>> Morandini<[email protected]>wrote: >>> >>>> There are some occurrences of >>>> >>>> container.size() == 0 >>>> >>>> scattered throughout the code >>>> (and fewer of container.size() != 0) . >>>> Many of them are harmless, i.e. whenever container >>>> is a vector. Some of them, however, >>>> are for maps of sets (e.g. dolfin/adaptivity/**Extrapolation.cpp:149 ), >>>> >>>> leading to completely unnecessary O(N) operations (racall that size() is >>>> O(N) for a map or a list). >>>> >>>> >>> While true for a list, it is not a problem for maps or sets: >>> >>> http://www.cplusplus.com/reference/stl/map/size/ >>> http://www.cplusplus.com/reference/stl/set/size/ >> >> >> I stand corrected >> >> >>> While a silly implementation of a list will be O(n) most good >>> implementations keep its size around. >> >> >> but please be aware that the "silly implementation" we are talking about >> is gcc's one: >> >> >> http://gcc.gnu.org/onlinedocs/libstdc++/manual/containers.html#sequences.list.size >> >> Marco > > > Yet another reason I hate gcc. Anywho the foo.empty() is better anyway as > it does represent the idea. >
Yes, I agree that if conveys the intention better. Garth > -- Andy > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : [email protected] > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp > _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
