March 2015 - Boost - lists.preview.boost.org

Transferring a library on Github
by Edward Diener 31 Mar '15

31 Mar '15

In order to get VMD under boostorg in order to begin the process of integrating the library into Boost for the release after the current pending one I tried to transfer the library as explained on the page https://svn.boost.org/trac/boost/wiki/NewLibFromGit. But I do not have the necessary admin rights for boostorg. How do I proceed ? I want to get VMD under boostorg and then do whatever is necessary to add it to the superproject and have it part of for regression testing.

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[detail] Bug in is_postfix_incrementable
by Edward Diener 31 Mar '15

31 Mar '15

There is a rather bad bug in is_postfix_incrementable in the detail/is_incrementable.hpp header file. I noticed this when I was looking at how I can remove the dependncies in is_incrementable.hpp on the deprecated Type_traits header files in Version2 of type_traits. The bug looks totally obvious to me. It's that the is_postfix_incrementable metafunction is derived from the is_incrementable_::impl<T> implementation rather than the is_incrementable_::postfix_impl<T> implementation. I am sure this was just a copy-paste problem but evidently has been in the header file from the beginning. Can we fast forward the simple fix to the new release ? I posted this just to be sure I haven't missed anything in the file. I believe that only the iterator library currently uses the is_incrementable and is_postfix_incrementable metafunctions in its tests. Since it is Boost detail no end-user should be using it. Still we should have it correct, shouldn't we, in our release ?

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Conflicts when building libraries at root
by Peter Dimov 31 Mar '15

31 Mar '15

On Windows, at least, when I do ./b2 toolset=msvc-8.0 at Boost root, I get error: Name clash for '<pstage\lib>libboost_system-vc80-mt-gd-1_58.lib' error: error: Tried to build the target twice, with property sets having error: these incompatible properties: error: error: - <warnings>all error: - <address-model>32 <architecture>x86 <warnings>on When I add --without-context --without-coroutine, I now get error: Name clash for '<pstage\lib>libboost_system-vc80-mt-1_58.lib' error: error: Tried to build the target twice, with property sets having error: these incompatible properties: error: error: - <asynch-exceptions>off error: - <asynch-exceptions>on So I add --without-test. error: Name clash for '<pstage\lib>libboost_timer-vc80-mt-1_58.lib' error: error: Tried to build the target twice, with property sets having error: these incompatible properties: error: error: - <asynch-exceptions>on <library>object(file-target)@10959 error: - <asynch-exceptions>off <library>object(file-target)@9953 Now where did _that_ come from. :-) Ah. --without-endian. Builds now. This is perhaps old news for some, but it looks like it doesn't play well with our simple build instructions. Or maybe it doesn't occur on the master branch, so we don't care? I haven't checked yet. It's also perhaps an indication of a deeper problem. I can use b2 --with-test and have 'test' built; it builds its dependencies (system, chrono and timer) with <asynch-exceptions>on in bin.v2, and if I use it from within Boost.Build, it will link to them. But if I stage (or install) Boost.Test, and then stage or install Boost.System separately, Boost.System will be built with <asynch-exceptions>off. So the library user who just has headers and binaries will link those, potentially creating a conflict, which may in this case be benign. Or not.

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[Container] const boost::container::vector is mutable??
by Eric Niebler 31 Mar '15

31 Mar '15

Why are the elements of a const boost::vector mutable through its const_iterator? #include <boost/container/vector.hpp> int main() { using C = boost::container::vector<int>; C c{1,2,3,4}; C const & r = c; r[0] = 42; // Error, good. *r.begin() = 42; // Compiles! huh?? } -- Eric Niebler Boost.org http://www.boost.org

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how to contact iterator developers
by Claas H. Koehler 31 Mar '15

31 Mar '15

Hi! About a week ago I sent a question about a specific bug to the iterator developers via this list and haven't received any feedback yet. Is this list not the right place to ask such questions or are there currently no active iterator developers managing the project ? Regards Claas

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Release deadlines
by Marshall Clow 30 Mar '15

30 Mar '15

Just a reminder that we’re coming up on a release; and if you have changes that you want to see in the release (I know *I* do), you should get them in ASAP. Check them into develop, and then, once the tests have cycled successfully, merge them to master. Please do not merge anything to master w/o permission from the release managers after the start of April (11:59 PM next Tuesday PDT). Also, if you know of problems with the current state of the master branch that would preclude releasing it, please let us know (preferably *before* next Wednesday). Thanks for your help with the releases. — Marshall & the rest of the release managers.

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[serialization] Passing literals to oarchive
by Bjorn Reese 30 Mar '15

30 Mar '15

Currently we cannot pass literals directly to an oarchive like this: oarchive << 42; since compilation fails in interface_oarchive.hpp, as the operator<< only takes parameters by reference. We can remedy this by changing operator<< to take the parameter by const-ref instead, as show below. Is there any reason not to do this? --- a/include/boost/archive/detail/interface_oarchive.hpp +++ b/include/boost/archive/detail/interface_oarchive.hpp @@ -59,7 +59,7 @@ public: } template<class T> - Archive & operator<<(T & t){ + Archive & operator<<(const T & t){ this->This()->save_override(t, 0); return * this->This(); }

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[mpl] Is BOOST_MPL_PP_TOKEN_EQUAL publicly usable ?
by Damien Buhl 30 Mar '15

30 Mar '15

Dear Boost.MPL developers, I was coming up to something really similar to BOOST_MPL_PP_TOKEN_EQUAL ( http://www.boost.org/doc/libs/1_57_0/boost/mpl/aux_/preprocessor/token_equa… ) in Boost.Fusion to fix warnings that my changes generate in MSVC 8 ( As discussed on this list as *[boost] MSVC warnings for BOOST_PP_IS_EMPTY in Boost.Phoenix* ) Instead of having a second implementation of the same macro within Boost.Fusion, is it ok if I use BOOST_MPL_PP_TOKEN_EQUAL from MPL ? I'm asking this because it isn't documented anywhere and is in mpl/include/boost/mpl/aux_/preprocessor/token_equal.hpp which sounds like a private header. Possibly there are reasons for not being documented ? Cheers, -- Damien Buhl

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Re: [boost] [Locale] Boost.Locale cannot Run in Visual Studio 2010
by Artyom Beilis 30 Mar '15

30 Mar '15

> >I have been trying to learn Boost.Locale Module. Consider this >http://www.boost.org/doc/libs/1_55_0/libs/locale/doc/html/conversions_8cpp-… >example. The code gets successfully compiled but when I try to run it, it >gives the error > >Unhandled exception at 0x74d34b32 in LearningCPP.exe: Microsoft C++ >exception: std::bad_cast at memory location 0x00a6fa48.. > >I have attached the stack-trace of the program also. Here it is: > > [snip] > > Did anyone faced this issue when using Boost.Locale in Visual Studio 2010? > If so, how do I resolve this issue? 1. Do you use latest version of MSVC or public beta (there was facet related bug there)2. Make sure you don't mix debug and release code (which can be very likely stuff there) on both boost and its dependencies (icu if you use one) Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/

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[GSOC] Request for proposal review and feedback
by Divyansh Gupta 30 Mar '15

30 Mar '15

Hi BOOST, I had submitted my proposal for the enhanced vector and deque project on 17th March, but I haven't received any comments yet. It would be great if I could get some feedback on the proposal, so that I can make any necessary changes while that's allowed. Thanks a lot. Regards, Divyansh Gupta PS- Here's the link to the proposal: https://www.google-melange.com/gsoc/proposal/review/student/google/gsoc2015…

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[thread] Alternate future implementation and future islands.
by Giovanni Piero Deretta 29 Mar '15

29 Mar '15

[cc'ing a few of the participants of the old thread] Hi All, Back in January, there was an interesting long thread about the problem of interoperation between futures of different libraries and the ability wait for heterogeneous futures. Different solutions were discussed like standardizing the future shared state or having an unified kernel wait object. I just wanted to share my attempt on a solution on the problem. The code can be found at https://github.com/gpderetta/libtask/blob/master/future.hpp (other interesting files are shared_future.hpp event.hpp and tests/future_test.cpp). It is an implementation a subset of the current boost and std future interface. In particular it has promise, future, shared_future, future::then, wait_any, wait_all. Most important missing piece are timed waits (for lack of, ahem, time, but should be easy to implement). The implementation requires c++14 and is only lightly tested, it should be treated as a proof of concept, not production-ready code. A few key design points: * The wait strategy is not part of the future implementation (although a default is provided). future::get, future::wait, wait_all and wait_any are parametrized by the wait strategy. * The design aims to streamline and make as fast as possible future and promise at the cost of a slower shared_future (although there is room for improvement). * The wait strategy only deals with 'event' objects, which act as a bridge between the future and the promise. The event object is really my the core of my contribution; it can be thought of as the essence of future<void>::then; alternatively it can be seen as a pure user space synchronization primitive. Other features of this implementation: * Other than in the blocking strategy itself, the future and promise implementation have no sources of blocking (no mutexes, not even spin locks). * The shared state is not reference counted. To demonstrate the generality of the waiting concept, I have implemented a few waiter objects. * cv_waiter: this is simply a waiter on top of an std::mutex + cond var. * futex_waiter (linux): an atomic counter + a futex, possibly more efficient than the cv_waiter * sem_waiter (posix): a waiter implemented on top of a posix semaphore. More portable than the futex waiter and possibly more efficient than the cv_waiter * fd_waiter(linux, possibly posix): a waiter implemented on top of linux eventfd (for portability it can also be implemented on top of a pipe); you can use select with futures! * task_waiter: a completely userspace based coroutine waiter which switches to another coroutine on wait and resumes the original coroutine on signal. * scheduler_waiter: another coroutine based waiter, but on top of an userspace task scheduler. On wait switch to the next ready task, on signal enqueue the waiting task to the back of the ready queue. I know that there is a plan to reimplement a new version of boost::threads, hopefully this implementation can contribute a few ideas. HTH, -- gpd

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[vmd] Updated VMD library
by Edward Diener 28 Mar '15

28 Mar '15

I have updated the VMD library which has been accepted into Boost based on the reviews and comments of others. The macro interfaces have been simplified and redesigned for easier use and the documentation has been updated to provide more examples and samples of using VMD in code. The library is currently at https://github.com/eldiener/variadic_macro_data. The latest library code is now on the 'master' branch and the code that was reviewed is on the 'Version17' branch. The VMD library is a library of variadic macros which enhance the functionality in the Boost preprocessor library ( Boost PP ). The main focus of the library is the parsing/identifying of a subset of C++ preprocessor data types and of all Boost PP data types. This allows enhanced preprocessor metaprogramming based on the type of macro input. The library has been successfully tested on gcc 4.3.0 on up, VC++ 8 on up, clang 3.3 on up, and Intel 12.1 on up. The library has been tested on Windows and Linux. Comments, questions, bug reports are welcome.

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sun toolset buggy and outdated?
by John Maddock 28 Mar '15

28 Mar '15

I'm trying to test the new Oracle-solaris compiler but I'm running into Boost.Build issues. First off what looks like a bug, if I build with with b2 stdlib=native Then I *still* get stlport You can easily reproduce this on another platform with: cd libs/config/test ../../../b2 config_info toolset=sun stdlib=native -n -d2 which yields: sun.compile.c++ ..\..\..\bin.v2\libs\config\test\config_info.test\sun\debug\stdlib-sun-stlport\config_info.obj "CC" +d -library=stlport4 -g -erroff=%none -KPIC -DBOOST_ALL_NO_LIB=1 -I"..\..\.." -c -o "..\..\..\bin.v2\libs\config\test\config_info.test\sun\debug\stdlib-sun-stlport\config_info.obj" "config_info.cpp" Now for the outdated part: the oracle compiler (12.4) now supports three std lib options: 1) The default - I can't make this work in C++03 mode, but it's the only option that does work in C++11 mode (where it appears to be a recent GNU libstdc++ version). 2) STLPort - only works in C++03 mode. 3) Apache - only works in C++03 mode. So ideally we would probably have: stdlib=stlport, sets -library=stlport4 for both compile and link. stdlib=apache, sets -library=stdcxx4 for both compile and link stdlib=native, sets -std=c++11 for both compile and link. And yes I realise we're mixing up two different features here, but as they can't be mixed and matched anyway it at least gets things working. I guess the toolset should be renamed either "oracle" or "solaris" as well? If anyone has any ideas how to patch the toolset, I have a working virtual machine to test on (or you can do as I did and download a pre-build VirtualBox machine). Thanks in advance, John.

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[gsoc15] Please help rank GSoC 2015 student projects
by Niall Douglas 27 Mar '15

27 Mar '15

Dear Boost Community, The Google Summer of Code 2015 proposals for Boost are in, and we would deeply appreciate the community's help in ranking the proposals according to merit before the 6th of April. To vote, the process is easy: 1. Go to this page https://www.google-melange.com/gsoc/homepage/google/gsoc2015 and click the "Log in" button under Mentors and Administrators. 2. Now click "Create Profile" on the same page. Note that even if you registered last year, you must register again in 2015. Fill in the form. Note that after submitting it drops you at "Edit Profile", which is confusing. 3. Click "My Dashboard", then "Connect with organisations". 4. Choose "Boost C++ Libraries". 5. In the message box, write this: "I am a member of the Boost community and the email(s) I normally post to boost mailing lists with is <email>" filling in the email address(es) you normally use to post to boost mailing lists. This lets us verify that you are indeed a long standing member of the Boost community. 6. Once we approve your request, you will get an email with the subject "Welcome as organisation member". You can now return to the Dashboard on the GSoC website where there will be a new item "Proposals". 7. Work your way through as many of the 33 proposals as you can. You can score them using the stars at the bottom of each proposal page, taking care to read any comments by the mentors and students if present. PLEASE try to rank some of the lowest scored proposals, every year we get a lot of people who only rank the top five and don't bother with the rest. Try to score on the priority basis of: (i) ability to write quality C++, using the programming competency test or samples of programming the student supplied. (ii) proposal quality and your best estimate of the student's understanding of how best to solve the problem at hand. Bear in mind a gifted programmer with a strong work ethic but poor English may appear to not understand the problem as well as native English speakers, this is why we have asked for examples of their programming competency. (iii) if the student came early to the mailing lists to ask for help writing the proposal (the mentors who helped them with their proposals have usually indicated this in the private comments). (iv) usefulness/appropriateness of the feature or work being proposed. Remember a good GSoC is more about getting promising new engineers into Boost and C++ than necessarily getting code to pass Boost peer review in a single summer. 8. Optional: If a proposal looks especially great to you and you feel able to mentor a student this year, please slide the "wish to mentor" button. Just because a proposal already has willing mentors does NOT mean you should not add yourself - if you can substitute for an existing mentor, that may mean we use that mentor for another proposal. As you know, Google Summer of Code is usually worth $42,000 - $48,000 to Boost each year, and a successful GSoC raises our visibility and reputation in the wider open source community. Our thanks to you in advance for taking the time to vote. Niall Douglas Boris Schäling --- Boost C++ Libraries Google Summer of Code 2015 admin https://svn.boost.org/trac/boost/wiki/SoC2015

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[SmartPointers] Determine interest in a new pointer wrapper class "flex_ptr"
by Jakob Riedle 27 Mar '15

27 Mar '15

Hello Boost Community, In the last few weeks, I heavily felt the lack of boost not having a more lightweight solution to a "not-necessarily-owning" pointer-wrapper than shared_ptr. shared_ptr is quite slow in the context that I need it to work. Furthermore it always is owning, even though ownership is shared in between instances. This is unhelpful, if you have an std::list of both non-owning and owning pointers. Hence, if you do not want to use shared_ptr all over your project, or especially want to interact with C, you need a not-necessarily-owning pointer-wrapper. This is why I collected some ideas on how to improve the situation. I came up with a little class named 'flex_ptr', that can hold both strong and weak references (therefore the name 'flexible', but it can also be 'the name of whatever proves itself to be good ...'). It keeps track of whether the held pointer is strong or weak. The Class doesn't need reference counting, since an Instance either is owning, or non-owning. Ownership is transferred between Instances using the default Move/Copy behavior. By Default the Constructor takes a pointer and treats it as a weak one. This is required, since this class aims on being used only at places, that are ought to be able to but not necessarily own objects. (Excuse me for the long sentence) A flex_ptr instance holding a strong pointer is created using a static non-member method named 'make_owning_flex', which accepts an rvalue pointer. As a result, it is not required to use the class at every single pointer occurrences in the project, but only at places, where the programmer wants to allow but not force strong references. The flex_ptr class is easily integrated into existing code using unique_ and shared_ptr's: One could think of - a constructor accepting a const lvalue reference unique_ptr, creating a (flex_ptr-instance holding a) weak reference, - a constructor accepting an rvalue unique_ptr, creating a strong pointer, that is owning an object it received from unique_ptr, - as well as a constructor taking a const lvalue reference shared_ptr, creating a weak pointer. Résumé: This pattern allows outright memory management, it uses less memory than shared_ptr (because no reference counting object required), therefore is faster, allows well-defined interactions similar to unique_ptr (especially at interaction with C) and thus fills a yet unclosed gap in the boost library as well as the Standard. Since this is (only) my personal opinion, I'd like to see how people feel about this 'gap' and think about this addition in the library (however the pattern may be implemented in the end). Regards, Jakob Riedle

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GSoC 2015 Boost Compute Proposal
by Aditya Avinash Atluri 27 Mar '15

27 Mar '15

Hi, This is my proposal. Please suggest edits. Thank you!! :) *Personal Details:* Name: Aditya Atluri University: The George Washington University Major: Computer Engineering Degree: MS Email: adityaavinash1(a)gmail.com Homepage: adityaatluri.github.io Availability: 1. 7 days a week 2. 27 April to 28 August 3. Nothing. *Background Information:* *Educational Background:* I did my undergrad from Indian Institute of Technology, Dhanbad, India. Currently, I am pursuing my Masters at The George Washington University. The courses I have taken are, High Performance Computing, Advanced Computer Micro Architecture, Computer Graphics, Advanced Topics in Computer Graphics, VLSI Design, Low Power VLSI Design, Compiler, Machine Learning. I have did lots of projects in these courses which can be seen on my website and in my bio[1]. *Programming Background and Interests:* I am researcher, I program GPUs with IRs, writing work arounds and using a specific hardware for other applications (example, implementing ray tracing on rasterizer on GPUs, using tessellators for generating procedural textures). I wrote high productive parallel programming abstractions for GPUs[2]. I presented my work at GTC 2014. For this work, NVIDIA supported me with a couple of Tesla K40s. As CUDA, OpenGL, OpenCL, Metal, Thrust are C/C++ APIs I use C++ extensively. I also create databases on GPUs which is now in deep interest from NVIDIA, Google and MapD. I worked with Mesa, Open Source graphics drivers for Linux to build ARB_shader_atomic_counters for R600 backend. I also worked at IBM software labs, where I worked majorly on Java. *Why I opted Boost?* I use boost on daily basis as a part of PyCUDA. I write work arounds which involve some of boost libraries. The next thing I am interested in Boost is its Compute library. I have used other GPU STL style libraries but, none are as good as Compute (simple and elegant). I couldn't contribute to Compute via GSOC last year due to my CPT. I don't want to lose that chance again. This time, I want to take Boost.Compute to a whole new level. I like to program anything related to GPUs, compilers, drivers, APIs. *Interest in Boost.Compute:* As I have mentioned earlier, I am all-in for anything related to GPUs. Either graphics or compute libraries. I believe in Boost.Compute that it can be a widely used API, hence I want to make it more powerful and more useful. *Previous Work:* I work on graphics drivers on regular basis. I write loads of OpenGL compute and shader code (part of my TA job and Mesa testing on local systems). I am good at using APIs, making optimizations, less memory footage. For example, increasing the number of draw calls per second without stalling CPU, writing shaders with more ALU operations than Load/Store operations. Aligning data properly to memory width size, minimizing padding done by compilers by struct unrolling (to get exact multiple of word size). These are a few of the optimizations I do every day. I am currently working on running Metal Shading Language on Intel processors (using AVX).[3] *Plans beyond SoC*: I want to extend Compute to ARM and Qualcomm devices that support both OpenCL and ARM Neon. This brings all "compute-intense" APIs under one roof. C++ 98/03 - 03 C++ 98/14 - 03 C++ STL - 4 Boost C++ Libraries - (Knowledge: 2, Usage: 2) Git: 3 I program using Visual Studio and Xcode. Using Terminal on Linux. I am good with Doxygen. *Project Proposal:* Introduction: Boost Compute library is so far the best portable STL-like C++ library for accelerated computing leveraging the underlying parallel hardware. Boost Compute works well on OpenCL compatible desktop/notebook devices. In this project, we implement Boost Compute on mobile devices. Current mobile devices doesn’t provide good STL style abstractions that are accelerated by SIMD and OpenCL. With the introduction of Metal graphics API for iOS devices, development of compute application for non-iOS and iOS devices requires knowledge multiple skill sets. With this project, we bring all compute abstractions of different mobile devices under one roof that is, Boost.Compute. Project Goals: Make C++ extensions from Objective-C. Integrate device containers to Boost.Compute front end. Make Metal API data types visible to user through Boost.Compute. Implementing BOOST_COMPUTE_FUNCTION() to run custom kernels. Most important, implementing algorithms for Boost.Compute on iOS devices using Metal Shader Language. *Implementation:* Building Boost.Compute APIs for iOS devices. - Metal graphics APIs are used as backend to create Boost.Compute APIs in conjunction with Metal Shading Language Make C++ extensions from Objective-C. - Metal is Objective-C graphics API whereas Boost.Compute is C++ compute API. Hence a bridge between these two APIs should be made to use Compute on iOS devices. Hence, we build C++ extensions from Objective-C APIs. As C++ is also used in building iOS apps, writing Boost.Compute for iOS devices makes it easier to leverage compute performance from an iOS app. Build resource management Metal API backend for Boost.Compute - Here we develop infrastructure which make "algorithms" run on the hardware. Like, creating automated CommandQueues, CommandBuffers, Resources (buffers or textures) - As Metal APIs does not have ‘context’ related API, mapping can be done to Metal command buffer API. Some OpenCL APIs which are natively available (using in Boost.Compute) are not present in Metal API, appropriate mapping from Boost.Compute to Metal API commands will be found. Integrate device containers from Metal API to Boost.Compute front end. - Boost.Compute provide vector and array containers. These should be declared in Metal and integrated to Boost. Device containers include, device vectors, initializing vectors, moving vectors, similarly for arrays, etc., and their STL type functionality (.size(), .length()) - Implementing iterators for the containers should also be done. Make Metal API data types visible to user through Boost.Compute. - Mapping Metal data types to current Boost.Compute data types, while making them consistent with current Boost.Compute APIs. Certain new data types to Metal are being added which improve the performance and decrease memory footprint. Making these visible to the programmer and building building algorithms with them is done in this section. Implement algorithms for Boost.Compute in Metal Shading Language. - This makes the biggest challenge as Metal compute shaders support two modes of execution (fast and precise modes). Algorithms written in each mode should be iterated over to judge the best performance without losing precision for speed. Testing the existing Boost.Compute code on iOS devices and debugging for errors. - With Metal emulators not being available for Xcode, hardware testing will be done[4]. *Timeline:* The timeline is straight forward, for details check Implementation section. 27 April – 25 May: Community bonding, testing the Xcode and iOS infrastructure to find any possible build problems. Build a test run environment (iOS app) to check any other hardware/software issues in deploying Metal API code to iOS device. 25 May – 10 June: Wrap C++ Metal extensions with C++, submit patches. 10 June – 25 June: Implement data types and containers for Boost from C++ Metal APIs. Make appropriate changes to the code after getting feedback from community. Submit patches. 25 June – 3 July: Review community feedback and change patches accordingly. 3 July – 3 August: Write BUILD_COMPUTE_FUNCTION() and Boost.Compute algorithms on Metal Shading Language and integrate it to Boost.Compute Metal APIs. Submit patches. 3 August – 17 August: Write tests and debug by running them on iOS test app 17 August – 28 August: Cleaning up code and review with community. Available Hardware: iPhone 4s, 6Plus, Mac Mini. Mentor: Kyle Lutz (kyle.r.lutz(a)gmail.com) *Competency:* The project I started which creates the actual Metal API, is iaMetal (Metal for Intel processors)[3]. It does not uses Metal SL, it converts Metal SL to AVX extensions. [1]. https://github.com/adityaatluri/adityaatluri.github.co/blob/master/CV.md [2]. https://github.com/urutu/Urutu [3]. https://github.com/iaMetal/iaMetal [4]. https://devforums.apple.com/message/971605#971605 -- Regards, Aditya Avinash Atluri, Graduate Student, Electrical and Computer Engineering, The George Washington University, Washington, DC.

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[asio][android][clang-x86] cannot locate symbol "___tls_get_addr"
by Dmitry Moskalchuk 27 Mar '15

27 Mar '15

As you can see at http://www.boost.org/development/tests/master/developer/asio.html, there are many fails on Android/x86, when tests are built by clang. There was ticket filed to CrystaX NDK tracker about that: https://tracker.crystax.net/issues/912. After some research, I've found reason of fails and created pull request for Boost.Asio: https://github.com/boostorg/asio/pull/17. Shortly speaking, there is intersection of several bugs - one is inability of clang to emulate thread-local variables without support from underlying runtime (gcc can do that), and second is misconfiguration in Boost.Asio headers. I've tested locally with change from https://github.com/boostorg/asio/pull/17 and all '___tls_get_addr' errors disappeared. Now I'm waiting for that pull request to be merged into upstream, but I don't see any activity in Boost.Asio repository. Is there something wrong with my pull request? It's very simple so I wonder why it not yet merged? I'd like to see it merged to the upstream (including 'master') before 1.58 release - just because this bug cause not only Boost.Asio fails, but several others libraries too. -- Dmitry Moskalchuk

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[GSoC] Proposal for uBLAS
by Ganesh Prasad 27 Mar '15

27 Mar '15

Hello everybody, Here is the final draft of my proposal for GSoC'15 and I have made it public. https://www.google-melange.com/gsoc/proposal/review/student/google/gsoc2015… The same text can be found on Gist at https://gist.github.com/GnsP/72dce0ac96394f54797c Reviews are requested and welcome. Best wishes Ganesh Prasad

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No automatic super project commits at the moment.
by Daniel James 27 Mar '15

27 Mar '15

Hi, Github is currently going through a DDOS attack, which is why the super project isn't getting updated for new commits. I imagine testers will also have problems running. Daniel

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GSOC 2015 Proposal
by Aditya Avinash Atluri 27 Mar '15

27 Mar '15

Hi, This is my proposal for GSoC 2015. Please suggest me some edits. Thank you!! :) https://www.google-melange.com/gsoc/proposal/review/student/google/gsoc2015… -- Regards, Aditya Avinash Atluri, Graduate Student, Electrical and Computer Engineering, The George Washington University, Washington, DC.

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Proposal "Enhanced vector and deque containers" project (GSoC 2015)
by Nico Hartmann 27 Mar '15

27 Mar '15

Hello everyone, as a student with quite some experience developing C++ I finally decided to participate in an open source project instead of just writing all the code for myself. To do so I chose to join the boost community in the course of this year's Google Sommer of Code. Therefore I wrote a proposal for the "enhanced vector and deque containers" project that really drew my interest. I like to invite you to take a look at my proposal as well as the requested implementation of a small vector class (including unit tests) to prove my capability to write C++ code. Thank you very much Nico project announcement: https://svn.boost.org/trac/boost/wiki/SoC2015#a5.Enhancedvectoranddequecont… project proposal (GSoC 2015): https://www.google-melange.com/gsoc/proposal/review/student/google/gsoc2015… small vector class implementation on github: https://github.com/nh-/gsoc_vector

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GSOC 2015 Proposal
by vivek dhiman 26 Mar '15

26 Mar '15

Hello all This is my proposal for GSoC 2015. http://www.google-melange.com/gsoc/proposal/public/google/gsoc2015/vdhiman/… It would be awesome if you guys could suggest some changes/edits. Thanks Vivek Dhiman

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Boost.uBLAS a library for matrix computations Project: Data Frame
by Sahba E 26 Mar '15

26 Mar '15

Hello all, My name is Sahba Etezad. I'm studying masters of Computing Science in Simon Fraser University, Canada.I'm really interested in working on ublas library and matrix computations. Particularly, I'm really passionate about the data frame project. My thesis concerns graph embedding so I've been working with Boost graph library for over a year now. I've been also coding in Matlab for over 4 years, and I think my familiarity with matrix operations and all that can be an asset for this project. I've finished implementing the competency code. https://github.com/setezad/ublasAnd I know it's really last minute, but I'd really appreciate it if you would give me some advice on what I should include to provide a precise project proposal. It has been mentioned that a data frame similar to R should be implemented with extension to implementing the summary and aggregate functions. I studied the two links provided in the project description ( http://pandas.pydata.org/pandas-docs/dev/generated/pandas.DataFrame.html, and http://cran.r-project.org/web/packages/data.table/index.html ). Now my question is knowing that a data frame can have countless attributes and methods, should I specify what attributes and methods I'd like to implement? Or will it be decided later and need not to be proposed by me? Thank you very much. Regards,Sahba Etezad

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[SORT] Parallel Algorithms
by Francisco José Tapia 26 Mar '15

26 Mar '15

Sorry by the delay, As promised, the sorting parallel algorithms On my computer (Quad Core) the GCC std::sort and stable_sort are slight faster than my version of intro_sort and merge_sort (stable sort is a synonym of merge_sort). In other computer with an Intel I3, my algorithms are slight faster than in the GCC version. Trying to optimize the parallel implementation. I modified the parallel version for to use the std::sort and std::stable_sort. The parallel_sort version response good, but the parallel_stable_sort increase the time around a 60% compared with the version with countertree::parallel_merge_sort . After many test, I discover the cause of the problem. The demonstration is in the test_stress_sort_01.cpp. In this program we have a big vector of 100 000 000 elements uint64_t. The program make parts of the same size for each HW core. On my computer 4 parts and 4 cores. The program execute the part sequentially checking the time, and after do the same but in parallel, each thread sort a part, and check the time. This is done with the std::stable sort and countertree::merge_sort. The data input is the same for all. The next lines are the result show max. OpenMP threads: 4 (4 processors) Sort of 100000000 elements in a vector --------------------- Random elements, few repeated ( rand() )----------------------- Stable Sort Part 0 secs :2.77955 Part 1 secs :2.75015 Part 2 secs :2.76068 Part 3 secs :2.76284 Parallel Sort secs :8.49796 Countertree stable sort Part 0 secs :2.72802 Part 1 secs :2.71614 Part 2 secs :2.72074 Part 3 secs :2.722 Parallel Sort secs :4.80692 Surprisingly the parallel sort with countertree::stable_sort is much more faster than the sort with std::stable_sort in the GCC 4.8 and 4.9 compiler. This is the secret of the speed of the countertree::parallel_merge_sort. This is very important, because when the size of the elements is small, the GCC and the countertree algorithms have similar performance. But when the size of the elements grow, the std::stable sort is slower than the countertree::merge_sort. This difference is increased in the parallel version. The next lines are part of benchmark_sort_05.cpp *************************************************************** Sort of N = 6250000 elements of size 128 ***************************************************************** Random elements, few repeated ( rand() )----------------------- STL std::sort :2.9188 secs countertree::intro_sort :2.87864 secs parallel::sort :2.46113 secs tbb::parallel_sort :1.86458 secs countertree::parallel_sort:1.89263 secs std::stable_sort :8.77963 secs countertree::merge_sort :5.70694 secs parallel::stable_sort :8.03946 secs countertree::parallel_merge_sort :4.90815 secs I have in mind a new version of the stable sort in order to improve the speed, reducing the number of internal copy of elements. I hope to have time in Christmas, but I can't guarantee. If the results are the expected I will send you You have too, a version of indirect_sort, which sort pointers to the elements, and at end sort the elements according the pointers. You can replace any sort algorithm by their indirect version, obtaining the same results, with the only difference of the time needed. You have a benchmark_indirect_sort.cpp where see the comparison of the time needed of several sort methods and their indirect version with elements of different size. This code is a preliminary version, done for my countertree library. If you consider useful, I will change the name space and document the code, the algorithms and the ideas obtained from the benchmarks. Please feel free for ask me any question or for to modify or change anything. The goal is to provide good sort methods to the users. In the zip file you have the code and a file with a description of each code. Yours

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[Locale] Boost.Locale cannot Run in Visual Studio 2010
by Sarvagya Pant 26 Mar '15

26 Mar '15

I have been trying to learn Boost.Locale Module. Consider this http://www.boost.org/doc/libs/1_55_0/libs/locale/doc/html/conversions_8cpp-… example. The code gets successfully compiled but when I try to run it, it gives the error Unhandled exception at 0x74d34b32 in LearningCPP.exe: Microsoft C++ exception: std::bad_cast at memory location 0x00a6fa48.. I have attached the stack-trace of the program also. Here it is: KernelBase.dll!74d34b32() [Frames below may be incorrect and/or missing, no symbols loaded for KernelBase.dll] KernelBase.dll!74d34b32() > msvcr100d.dll!_nh_malloc_dbg(unsigned int nSize, int nhFlag, int nBlockUse, const char * szFileName, int nLine) Line 302 + 0x1d bytes C++ msvcr100d.dll!malloc(unsigned int nSize) Line 56 + 0x15 bytes C++ LearningCPP.exe!std::use_facet<boost::locale::converter<char> >(const std::locale & _Loc) Line 526 C++ LearningCPP.exe!boost::locale::to_upper<char>(const char * str, const std::locale & loc) Line 225 + 0x9 bytes C++ LearningCPP.exe!main() Line 170 + 0xc4 bytes C++ LearningCPP.exe!__tmainCRTStartup() Line 555 + 0x19 bytes C LearningCPP.exe!mainCRTStartup() Line 371 C kernel32.dll!75268543() ntdll.dll!776bac69() ntdll.dll!776bac3c() Did anyone faced this issue when using Boost.Locale in Visual Studio 2010? If so, how do I resolve this issue? *PS:* I have used option Use Unicode Character Set under the Character Set option of Visual Studio. I believe the libraries are correctly linked too. -- *sarvagya*

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