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[GSOC 19] Boost.ublas project Idea
by Amit Singh 02 Feb '19

02 Feb '19

Hi, My name is Amit Singh and I’m a 2nd year student. 1. I have studied last years ublas stats project and before that ublas lacked any statistics features, I would like to take boost.ublas stats further with 1. Linear Regression 2. Logistic Regression 3. Rigid Regression 4. Kernels ( Exponential Kernel, Gaussian Kernel, etc) 5. Correlation (Pearson product-moment correlation, Linear correlation, etc) 2. In ublas there is no expression solver which can solve a expression and assign the value to variable for ex:- A. matrix<double> m = “A^2 * (B * A^-1) + (det(A) * I)”; B. matrix<double> m = “A + 3” ; =>[ m = A + 3*I ] 3. In ublas to modify matrix you have to iterate using for loop. I’m hoping to create a function similar to transform in c++ or map in javascript 1. This is my small machine learning library that I implemented in c++ https://github.com/amitsingh19975/ML Would anybody be interested in mentoring my project for gsoc 19? or help me to improve my project ideas.

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[thread] Passing function with parameters to boost::barrier
by André Offringa 01 Feb '19

01 Feb '19

Hi Boost developers, I'm having a problem with passing a completion function to a boost::barrier, causing a segfault, and I suspect it is a bug in the barrier code. The following is a minimal example that shows the problem: #include <boost/thread/barrier.hpp> void func(int) { } int main() { boost::barrier b(1, std::bind(func, 42)); b.wait(); } Running inside gdb and doing a bt shows some infinite recursion happening, starting with: #0 0x000055555555e41a in boost::thread_detail::decay_copy<boost::detail::nullary_function<void ()>&>(boost::detail::nullary_function<void ()>&) ( t=<error reading variable: Cannot access memory at address 0x7fffff7feff0>) at /usr/include/boost/thread/detail/move.hpp:355 #1 0x000055555555d814 in boost::detail::nullary_function<void ()>::nullary_function<boost::detail::nullary_function<void ()>&>(boost::detail::nullary_function<void ()>&) ( this=0x7fffff7ff0c0, f=...) at /usr/include/boost/thread/detail/nullary_function.hpp:81 ... When I change "std::bind(func, 42)" to just "func" (and declare func without parameters), it does work and the program exits normally. Passing a lambda to barrier (e.g. barrier(1, [&]() { func(0); } ) ) causes the same segfault, and the same holds when I change std::bind to boost::bind. I'm using Boost 1.67 on Debian Linux, amd64, gcc 8.2.0. Is this a bug? Cheers, André

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[asio]https significantly reduce performance
by lx 31 Jan '19

31 Jan '19

Hi Boost experts: I build a https server from asio example of server2, let it support ssl.we use the codes from: *https://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/example/http/server2/main.cpp <https://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/example/http/serv…>* *https://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/example/ssl/server.cpp <https://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/example/ssl/serve…>* I complie the codes with boost_1_64 and openssl-1.1.0j, the commed line of complie is: *g++ -g -Wall -o https_server2 *.cpp -I/usr/local/include/ -I/usr/local/openssl-1.1.0j/include -L/usr/local/openssl-1.1.0j/lib -I/usr/local/boost_1_64_0/include /usr/local/boost_1_64_0/lib/libboost_thread.a /usr/local/boost_1_64_0/lib/libboost_system.a -Wl,-Bstatic -lglog -lunwind -Wl,-Bdynamic -lpthread -lcrypto -lssl -ldl -lrt* I test the https_server2 by ngrinder, the TPS is just 400, If I test is just http request , the TPS is 36000. So https significantly reduce performance. The perf top result is: [image: 1.png] The top result is: [image: 2.png] When I test it by http request, the top result is: [image: 4.png] I have push the codes on github. https://github.com/lxlenovostar/Programming_language/tree/master/cpp/test/s… I test 2, 4, 8, 24, 32 threads,but this can't improve the TPS.I test the nginx with 32 worker process, The TPS is about 5000. So maybe lock in asio ? btw: cpu is 32 cores, and Intel(R) Xeon(R) CPU E5-2440 v2 @ 1.90GHz memory is 66GB. os is CentOS 6.5 kernel is 2.6.32 Thank you.

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[gsoc19][astronomy]
by Pranam Lashkari 30 Jan '19

30 Jan '19

Hello everyone, Last year I worked on the new astronomy library[0] and successfully completed GSoC with the help of my mentor *Vinícius dos Santos Oliveira*. In last GSoC, I completed basic coordinate systems and FITS file reading. *Current State of the Library:* Currently, this library has 7 basic astronomical coordinate systems implemented (Alt-Az, CIRS, ICRS, Galactic, Geocentric, Heliocentric, Supergalactic) which as actually wrappers around Boost::Geometry. IO module provides support for FITS reading. Right now, It can read primary HDU and image extensions. Development during GSoC can be found on the master branch[1] To preserve all the development done during the period of GSoC a separate branch was created after completion of GSoC named "gsoc18"[2]. All the development done after the period of GSoC can be found on develop branch[3]. No changes were merged to master after GSoC 18. *Idea for Boost GSoC19:* After communicating with the Boost::geometry community, integration of Boost::geometry and Boost::units is not supported and without using units scientific calculations are not error proof. As a result current coordinate systems can not be used with large projects as there are high possibilities of error. So this year I would like to implement Boost::unit with Boost::astronomy::coordinate to provide a robust astronomical coordinate system. Apart form this I would also complete the remaining parser for the FITS to read complete file including all types of extensions. I am targeting to complete the first coordinate system and FITS reader at the end of this GSoC and making this library ready for its first release. [0]: https://summerofcode.withgoogle.com/projects/5503102778605568 [1]: https://github.com/BoostGSoC18/astronomy/tree/master [2]: https://github.com/BoostGSoC18/astronomy/tree/gsoc18 [3]: https://github.com/BoostGSoC18/astronomy/tree/develop Thank you, Pranam Lashkari

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explicit-failures-markup.xml
by Niall Douglas 30 Jan '19

30 Jan '19

I'm trying to tell the Boost regression matrix that GCC 8 failures are to be expected using explicit-failures-markup.xml, but it seems to not be working: https://www.boost.org/development/tests/master/developer/outcome.html Here is my explicit-failures-markup.xml: <?xml version="1.0" encoding="utf-8"?> <explicit-failures-markup>  <library name="outcome"> <mark-unusable> <toolset name="clang-linux-3*"/> <toolset name="gcc-3*"/> <toolset name="gcc-4*"/> <toolset name="gcc-5*"/> <toolset name="gcc-mngw-3*"/> <toolset name="gcc-mngw-4*"/> <toolset name="gcc-mngw-5*"/> <toolset name="msvc-7*"/> <toolset name="msvc-8*"/> <toolset name="msvc-9*"/> <toolset name="msvc-10*"/> <toolset name="msvc-11*"/> <toolset name="msvc-12*"/> <toolset name="msvc-13*"/> <toolset name="msvc-14.0.*"/> <note author="Niall Douglas">Complete C++14 support is the minimum requirement.</note> </mark-unusable> <mark-expected-failures> <toolset name="gcc-8*"/> <note author="Niall Douglas">GCC 8 currently ICEs with Outcome's unit tests in C++ 17 or later.</note> </mark-expected-failures> </library> </explicit-failures-markup> What am I doing wrong? Thanks, Niall

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[lexical_cast] Assumed internal double conversion of float?
by Brian Kuhl 30 Jan '19

30 Jan '19

Hi Boost experts, We are chasing down some test failures with floats on VxWorks using the Dinkum clib and c++lib. We are testing with clang on Intel and Arm targets and GCC on PowerPC targets. An example failure at the bottom of this email. We have determined that boost::detail::lcast_get_precision<float>() is returning 9, well in access of the defined FLT_DIG of 6, or the practical float limit of 6.92. Specifically this code here: bool shl_real_type(float val, char* begin) { using namespace std; const double val_as_double = val; finish = start + #if defined(_MSC_VER) && (_MSC_VER >= 1400) && !defined(__SGI_STL_PORT) && !defined(_STLPORT_VERSION) sprintf_s(begin, CharacterBufferSize, #else sprintf(begin, #endif "%.*g", static_cast<int>(boost::detail::lcast_get_precision<float>()), val_as_double); return finish > start; } Where does boost::detail::lcast_get_precision<float>() come from, and why is it 9 ? Is it perhaps assuming some intermediate double conversion internally? In Dinkum's C library, Plager conservatively does not promote to a double, when converting to a string. Many thanks, Brian Wind River ->cmd "LD_LIBRARY_PATH=/opt/TestTriggerLocalPath/Workspace/vx7-boost/2019-01-13/vsb/app/boost/fsl_imx6_llvm_up_32_vxWorks/usr/root/llvm/bin;/opt/TestTriggerLocalPath/Workspace/vx7-boost/2019-01-13/vsb/app/boost/fsl_imx6_llvm_up_32_vxWorks/usr/lib/common" [vxWorks *]# cd /opt/TestTriggerLocalPath/Workspace/vx7-boost/2019-01-13/vsb/app/boost/fsl_imx6_llvm_up_32_vxWorks/3pp/BOOST/boost_1_68_0/status [vxWorks *]# run -x -t 0x01000000 -u 100000 -- ../bin.v2/libs/lexical_cast/test/lexical_cast_float_types_test.test/clang-vxworks/debug/cross-compile-vxworks/static-only-on/lexical_cast_float_types_test.vxe Launching process '../bin.v2/libs/lexical_cast/test/lexical_cast_float_types_test.test/clang-vxworks/debug/cross-compile-vxworks/static-only-on/lexical_cast_float_types_test.vxe' ... Process '../bin.v2/libs/lexical_cast/test/lexical_cast_float_types_test.test/clang-vxworks/debug/cross-compile-vxworks/static-only-on/lexical_cast_float_types_test.vxe' (process Id = 0x20482f10) launched. Running 3 test cases... unknown location(0): [4;31;49mfatal error: in "lexical_cast float types unit test/test_conversion_from_to_double": boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_lexical_cast> >: bad lexical cast: source type value could not be interpreted as target [0;39;49m ../libs/lexical_cast/test/lexical_cast_float_types_test.cpp(299): [1;36;49mlast checkpoint [0;39;49m unknown location(0): [4;31;49mfatal error: in "lexical_cast float types unit test/test_conversion_from_to_long_double": boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_lexical_cast> >: bad lexical cast: source type value could not be interpreted as target [0;39;49m ../libs/lexical_cast/test/lexical_cast_float_types_test.cpp(299): [1;36;49mlast checkpoint [0;39;49m

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GSoC 19
by Sandesh Ghanta 30 Jan '19

30 Jan '19

Hey All, I am Sandesh Ghanta, a junior majoring in Computer Science and Engineering. I am interested in contributing to boost and would also like to work with boost in GSoC 19. I am good with C, C++, data structures, algorithms and am currently trying to fix some issues in boost. As I am a beginner to boost I am currently confused as to what project to contribute to, I have been looking at the various issues available to see what I am interested in, but it would be really helpful if someone could guide me. Yours Sincerely, Sandesh Ghanta, FOSS@Amrita <http://amfoss.in> GitHub <https://github.com/sandeshghanta> | Codechef | <http://www.codechef.com/users/sandeshghanta>Codeforces <http://www.codeforces.com/profile/sandeshghanta>

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[gsoc2019] Searching for student
by Damian Vicino 30 Jan '19

30 Jan '19

Hi, I would like to mentor again this year. Some projects I'm particularly interested are getting safefloat or real ready for a formal review (both projects are from previous years and near completion). I'm also open to other projects too. Just ping me with an idea of what you would like to do. Best regards, Damian

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LEAF has been refactored, it now has a much simplified error handling interface
by Emil Dotchevski 29 Jan '19

29 Jan '19

LEAF is a C++11 error handling library for use in low-latency environments. I'm looking for a Boost Review Manager. Any one of you good people willing to volunteer? :) https://zajo.github.io/leaf/ Features: -Header-only, no dependencies. - No dynamic memory allocations. - Any error-related object of any movable type is efficiently delivered to the correct error handler. - Compatible with std::error_code, errno and any other error code type. - Support for multi-thread programming. - Can be used with or without exception handling.

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Wanted to contribute in your projects
by Jibran Zia 29 Jan '19

29 Jan '19

Hello I am Jibran Zia studying in National University of Information and Technology. I wanted to contribute in your projects for 2019 Google summer of Code. Please give me general overview about how I start working and from where I get code of your projects and how I will contribute in it... Thank you so much

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