Vicente Botet wrote:
> Message du 28/03/11 19:52 > De : "lcaminiti" > A : boost@lists.boost.org > Copie à : > Objet : Re: [boost] [local] Help for the Alternatives section > > > Thomas Heller-7 wrote: > > > > On Monday, March 28, 2011 07:03:46 PM lcaminiti wrote: > > > > > > Thomas Heller-7 wrote: > > > > > > > > On Monday, March 28, 2011 05:25:13 AM Jeremy Maitin-Shepard > > wrote: > > > > > On 03/26/2011 03:19 PM, Lorenzo Caminiti wrote: > > > > > > Hello all, > > > > > > > > > > > > I am updating Boost.Local docs and I could use > > a some help in > > > > getting > > > > > > the Alternatives section right > > > > > > > > > > > > http://svn.boost.org/svn/boost/sandbox/local/libs/local/doc/html/boost_local... > > > > > > > > > > You might include compile time and run time benchmarks, > > information > > > > > about error message quality, and polymorphic > > capabilities. > > > > > Additionally, you might note that with C++0x local > > classes can be > > > > used > > > > > with templates. > > > > > > > > Just did a quick test ... code is attached ... > > > > > > > > $ time g++ -O3 -I. -Wall -Wextra add.cpp -o add > > > > > > > > real 0m0.657s > > > > user 0m0.583s > > > > sys 0m0.067s > > > > > > > > $ time ./add > > > > 1e+12 > > > > > > > > real 0m35.641s > > > > user 0m35.618s > > > > sys 0m0.017s > > > > > > > > $ time g++ -O3 -I. -Wall -Wextra add_boost_phoenix.cpp -o > > add_phoenix > > > > > > > > real 0m3.385s > > > > user 0m3.160s > > > > sys 0m0.217s > > > > thomas@sunshine ~/programming/local $ time ./add_phoenix > > > > 1e+12 > > > > > > > > real 0m6.648s > > > > user 0m6.643s > > > > sys 0m0.007s > > > > > > > > > > This is not a fare comparison because add.cpp contains also local > > blocks and > > > exits while add_boost_phoenix.cpp contains only local functions. The > > > comparison should be made between add_boost_local.cpp and > > > add_boost_phoenix.cpp (see below). The example names got a bit > > confusing and > > > I will rename add.cpp to add_funciton_block_exit.cpp to avoid similar > > > misunderstandings in the future. > > > > Seriously? Did you even look at the files i attached? > > > > Ooops... no, I didn't. I have files with the exact same name in > sandbox/local/libs/local/examples so I assumed you attached these files... > > > > > Are you serious? Please write real benchmarks. By executing the resulting > > binaries of your code examples, the runtime is mainly dominated by process > > setup > > and the output on stdout. > > > > Take a look here: > > https://svn.boost.org/svn/boost/trunk/libs/spirit/optimization/ > > > > I have looked at the files you have attached now and I see what you mean. > Please scratch my previous benchmark numbers. I will run correct tests more > along the lines of what you suggested.
Hi Lorenzo,
To complete the performance comparison I will add a hand written test which should be used as reference implementation.
for (size_t i = 0; i < v.size(); ++i) { sum += factor * num; }
and a non-local functor so it can be used with foreach (which seems to perform better than the manual for (size_t i = 0; i < v.size(); ++i)
struct non_local_add { // Unfortunately, extra code to manually program the functor class. local_add(double& _sum, int _factor): sum(_sum), factor(_factor) {}
void operator()(double num) { // Body uses C++ statement syntax. sum += factor * num; std::cout << "Summed: " << sum << std::endl; }
private: // Unfortunately, cannot bind so repeat variable types. double& sum; // Access `sum` by (non-constant) reference. const int factor; // Make `factor` constant. } ;
int main() { double sum = 0.0; int factor = 10;
std::vector v(3); v[0] = 1.0; v[1] = 2.0; v[2] = 3.0;
non_local_add add(sum, factor);
// Non Local functor `add` passed as template parameter. std::for_each(v.begin(), v.end(), add);
std::cout << sum << std::endl; return 0; }
Yes, I am already looking as the non-local functor and the local functor without for_each as baselines.
In addition you can use Boost.Chrono so you measure exactly what you want to measure,i.e. the add instantiation + the foreach without setup and output.
I will look into Boost.Chrono. If you had time to sketch a bit of code on how I'd use Chrono in this case, it'd get me started. Thanks. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/local-Help-for-the-Alternatives-section-t... Sent from the Boost - Dev mailing list archive at Nabble.com.