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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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[threads / signals2] Win events replace by boost signals (threadsafe)
by Fu ji 26 Mar '15

26 Mar '15

Hello, I have to change win32 events with something portable so I decided to use boost.signals2. Right now I have something like: ret = WaitForMultipleObjets{ switch(ret) { case Timeout: something; break; case Event1: something; break; case Event2: something; break; }} and I think that the good idea is to replace this with something like that: for(;;){ Execute code from timeout, if event occurs interrupt and execute code which is responsible for event handling} but for test I write this: boost::signals2::signal<void()> signal; void SendSignal() { std::cout << "Send signal"; boost::this_thread::sleep_for(boost::chrono::milliseconds(200)); signal(); boost::this_thread::sleep_for(boost::chrono::milliseconds(2000)); } int main() { boost::thread t1(SendSignal); for (;;) { std::cout << "."; boost::this_thread::sleep_for(boost::chrono::milliseconds(100)); } auto c = signal.connect([]() { std::cout << "Signal receive" << std::endl; boost::this_thread::sleep_for(boost::chrono::milliseconds(1000)); }); return 0; } unfortunately this example is not working, what I've done wrong ? Best regards

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Server certificate expired on svn.boost.org
by William Gallafent 26 Mar '15

26 Mar '15

“The certificate expired on 2015-03-22 02:33” … ! -- Bill Gallafent.

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Removing auto_ptr/etc. from Boost
by Stephan T. Lavavej 25 Mar '15

25 Mar '15

Hi Boost devs, I need your help to get rid of auto_ptr forever. I want to implement C++17's N4190 "Removing auto_ptr, random_shuffle(), And Old <functional> Stuff", although it's going to take a while. In VC 2015, the removal will be opt-in (requested via a macro; I've already checked this in). My plan is for the removal to be opt-out in the version after that, and unconditional in the version after that. To achieve the opt-in removal, I've already eliminated the STL's internal dependencies on this stuff (nothing derives from unary_function/binary_function anymore, and shuffle() isn't directly implemented with random_shuffle() anymore). To prepare for the future of opt-out removal, I've also been removing usage from the compiler and other stuff. However, Boost is used in our tests in a number of places. What I'd like to ask is for Boost to begin removing its usage of this stuff (unconditionally or for VC 2015+, your pick). According to my understanding, only unary_function/binary_function and auto_ptr are used extensively by Boost, with the other stuff being used rarely or not at all. Thanks, Stephan T. Lavavej Senior Developer - Visual C++ Libraries

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[iterator] Bug #7526
by Claas 25 Mar '15

25 Mar '15

Hi! I was wondering, how the iterator developers intend to proceed with ticket #7526 (https://svn.boost.org/trac/boost/ticket/7526) Two fixes are available and seemingly just wait to be applied. One fix has been available for two years, and a more sophisticated (probably preferable) fix has been submitted 9 month ago. Has this simply been forgotten or are there any reasons, not to apply one of the available patches ?. Since I require the requested functionality, I would like to press the issue. If more support is required to fix this, please let me know. Since two years I have had to patch each version of boost manually to deploy this fix, which is a little frustrating. So I would gladly contribute, if this is required. Any update on the issue would be appreciated. Regards Claas

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[TypeSort] Automatic type sorting
by costis glynos 25 Mar '15

25 Mar '15

Hello,Is there any interest in a library which automatically sorts types from smallest to largest at compile time?The benefit would be the automatic Data Structure Alignment and potential improvement in performance.Foo<int,bool,Custom16ByteType,char,double,short> foo_1; //normal Foo<int,bool,Custom16ByteType,char,double,short> foo_2; //using the TypeSort output: size of foo_1 = 48 size of foo_2 = 32 Kind Regards, Constantinos

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