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[accumulators] Help understanding implementation of weighted accumulators
by Gabriel Redner 02 Oct '13

02 Oct '13

Hi folks, I am trying to implement a weighted accumulator, but I'm having trouble understanding a few things about the existing ones. Looking at the implementation of weighted_sum, I see (weighted_sum.hpp:37): template<typename Args> weighted_sum_impl(Args const &args) : weighted_sum_( args[parameter::keyword<Tag>::get() | Sample()] * numeric::one<Weight>::value ) { } My questions are: - It's taking the first sample from the args and multiplying it by a weight of 1. Isn't this wrong - ignoring the real weight of this sample? Shouldn't this produce incorrect results? - I've never understood anyways how there can be an initial argument during construction of the accumulator. I haven't found any explanation in the docs beyond "Maybe there is an initial value in the argument pack". Maybe? How? Probably more questions later. Thanks, -Gabe

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[thread] semaphore
by Tim Blechmann 02 Oct '13

02 Oct '13

hi all, i've submitted an implementation of semaphores for boost.thread to trac [1]. they provide an interface similar to boost.interprocess semaphores, with the exception of having chrono-style try_wait_for and try_wait_until members for timed_wait. the patch provides the following implementations: * win32 semaphores (tested with windows 8) * posix semaphores (tested with linux) * dispatch semaphores (tested with osx 10.8) * mutex/condition_variable/counter emulation the native implementations are much faster than the fallback, in microbenchmarks with high contention, i've seen a speedup of 30 to 80. would be great if they can be incorporated into boost.thread. comments/suggestions on the API are highly appreciated. cheers, tim [1] https://svn.boost.org/trac/boost/ticket/8797

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Is there interest in a Simulation library?
by Damian Vicino 01 Oct '13

01 Oct '13

Dear All, Following the on-going efforts on development and standardization of C++, especially application-oriented libraries, we are soliciting expression of interest within the C++ community for a new Boost library for building Discrete-Event simulators. We plan to build this new library on the latest features of the C++11 standard, for possible inclusion in a future version of the C++ standard. This work is based on our experience in building C++-based simulators for over 20 years, exploring various optimization and algorithms, and leading to a significant number of reseach publications. Writing a new version of a simulation library based on the latest features of the C++ language has started as new joint research project of University of Nice Sophia Antipolis, UMR CNRS 7172 (FR), INRIA Sophia Antipolis (FR), and Carleton University (CAN). Of course, anyone interested in joined this effort is more than welcome! Damian Vicino, PhD Candidate Université Nice Sophia Antipolis & Carleton University Dr. Olivier Dalle, Maître de Conférences, Université Nice Sophia Antipolis Pr. Gabriel Wainer, Carleton University

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[polygon] Release testing stalled... Missing source file.
by Rene Rivera 01 Oct '13

01 Oct '13

I commented out one of the test cases in the release branch because the source file for the test is non-existent. Rene. -- -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim - grafikrobot/yahoo

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testers blocked after changeset 85924 in trunk.
by Vicente J. Botet Escriba 01 Oct '13

01 Oct '13

Hi, the last change set that has been taken in account in trunk regression test is 85924. I'm expecting a lot of testers to cycle. Note that release regressing test are not blocked. Could someone explain what is happening? Best, Vicente

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Review request: Require compiler support for partial template specialization.
by Stephen Kelly 01 Oct '13

01 Oct '13

Hi there, Following from http://thread.gmane.org/gmane.comp.lib.boost.devel/243923/focus=243924 I am posting a more focused and specific request to review a patch to bump compiler requirements to require support for partial template specialization. This allows the removal of a lot of workaround code: src/boost-trunk{master}$ ../kf5/remove_def.py BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION src/boost-trunk{master}$ git diff --shortstat 192 files changed, 4798 deletions(-) Obviously I would not commit all of that as a single patch. Any comments? Thanks, Steve.

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Do/can we have a C++11 variadic integer list?
by Daryle Walker 01 Oct '13

01 Oct '13

I'm talking about this: template < std::size_t ...N > struct indices_too { using next = indices_too<N..., sizeof...(N)>; }; template < std::size_t N > struct make_indices_too { using type = typename make_indices_too<N - 1u>::type::next; }; template < > struct make_indices_too<0u> { using type = indices_too<>; }; I've written things like this 4 times for my prototype Boost classes, and I want it in Boost already so I can just reference that version. Something like it will come in C++14, but we could provide it here for C++11 users? Do we already have one? Here's how to use one: template < typename Function, typename T, class Tuple, std::size_t ...I > void apply_x_and_exploded_tuple_impl( Function &&f, T &&x, Tuple &&t, indices_too<I...> ) { using std::forward; forward<Function>( f )( forward<T>(x), forward<typename std::tuple_element<I, typename std::remove_reference<Tuple>::type>::type>(std::get<I>( t ))... ); } template < typename Function, typename T, class Tuple > void apply_x_and_exploded_tuple( Function &&f, T &&x, Tuple &&t ) { using std::forward; apply_x_and_exploded_tuple_impl( forward<Function>(f), forward<T>(x), forward<Tuple>(t), typename make_indices_too<std::tuple_size<typename std::remove_reference<Tuple>::type>::value>::type{} ); } Daryle W.

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orphaned tickets
by Joel Falcou 01 Oct '13

01 Oct '13

What's the protocol to handle lingering tickets of un maintained components. I wish #9169 and #9170 could be merged to trunk soonish. I cna do it myself but i dont want to breach any protocol. Regards

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REQ: Looking for access to a Haswell machine to test Boost memory transactions code
by Niall Douglas 30 Sep '13

30 Sep '13

Dear Boost Devs, Last night I may have implemented some Boost macro based support for simple memory transactions. Basically one does this: STLLockable lockable; ... BOOST_BEGIN_MEMORY_TRANSACTION(lockable) { // Transaction code } BOOST_END_MEMORY_TRANSACTION(lockable) This can turn into __transaction_relaxed, or Intel TSX falling back onto a spin lock. It's very simple, but it ought to work and with very significant performance improvements on TSX capable hardware. The problem is that I don't have access to an Intel Haswell CPU to test the code upon. I think its design is correct through introspection, but if a kind Boost dev could lend me access to their Haswell machine via SSH - or even just offer to debug some binaries for me, I would be very grateful. Thanks, Niall -- Currently unemployed and looking for work. Work Portfolio: http://careers.stackoverflow.com/nialldouglas/

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[release][interprocess] regression in Windows
by Joaquin M Lopez Munoz 30 Sep '13

30 Sep '13

As indicated by the regression testers, see for instance: http://tinyurl.com/qabv7dm This is affecting also Boost.Flyweight, which uses <boost/interprocess/detail/intermodule_singleton.hpp> for its intermodule_holder component. Thank you, Joaquín M López Muñoz Telefónica Digital

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