February 2020 - Boost-users

26 Feb '20

Hi, With regard to the article on Boost: Legendre-Stieltjes Polynomials - 1.66.0 | | | | Legendre-Stieltjes Polynomials - 1.66.0 | | | Can anyone help me to compute the stieltjes polynomials please? I'm coding in VBA and I'm looking for some recursive rules to calculate same. ThanksVick

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[GSoC] My piece of advice to students
by Mateusz Loskot 24 Feb '20

24 Feb '20

Dear Student, You are planning to participate in GSoC and develop some new features for the Boost libraries. Awesome! So, you want to introduce yourself to the community as soon as possible. Awesome! However, before posting your first question to the Boost mailing list, please, do read the official GSoC student guides [0]. All of it. [0] https://google.github.io/gsocguides/student/ I also recommend to read through other resources dedicated for students, especially this one from Google [1], one from a former student [2] as well as advice from Boost GSoC former student Louis Dionne [3]. [1] https://opensource.googleblog.com/2011/03/dos-and-donts-of-google-summer-of… [2] https://medium.com/@akshikawijesundara/google-summer-of-code-dos-and-do-not… [3] https://github.com/boostorg/wiki/wiki/Google-Summer-of-Code%3A-Advice-From-… Once you get through the general GSoC materials, it's a good idea to start browsing Boost resources, from intro [3] through netiquette [4] to wiki [5]. On [3] and [5] you will find links to past and current project ideas for Boost libraries. Browse it, read it, and learn what kind of projects Boost community develops during GSoC. Start thinking about what interests you, which Boost library, which project, what you'd like to develop as GSoC student. [4] https://www.boost.org/community/gsoc.html [5] https://www.boost.org/community/policy.html [6] https://github.com/boostorg/wiki/wiki Meanwhile, it's a good idea to "Make First Contact" [0]. Subscribe to the boost (developers) and boost-user or library-specific mailing list at https://lists.boost.org join Boost channels on Slack at https://cppalliance.org/slack/ and start discussing your participation, project ideas, etc. Although the student guides [0] use the phrase about "communicating directly with potential mentors", it does NOT mean exchanging private e-mails with mentors asking "Are you interested to mentor me?". GSoC does not work this way. In my opinion, the word "directly" means to interact directly with the community where, obviously, potential mentors are members too. The Boost organization and mentors will have chance to select students and projects they wish to mentor during the selection process - a secret, you can learn about it from GSoC guides for mentors [8]. Yes, the selection is a competitive process. [8] https://google.github.io/gsocguides/mentor/selecting-a-student Next, start discussing project of your interest, start asking questions, investigate ways to contribute to Boost, start working on competency tests Mind you, competency test is Boost way to verify minimum necessary skills. I personally think Boost should also ask for a bug fix [2] explains: "Some organizations make it a must for you to fix a bug in their code base before submitting a proposal but some do not. Your chances are always high if you can fix a bug in the code." Submitting a pull request with a small feature is also a good idea, something to discuss with mentors/maintainers of library of your interest Pull requests will allow you to gain hands-on experience with workflow of peer reviews, continuous communication, addressing problems, testing your solution, using the infrastructure, being exposed to stress of 'annoying' requests from maintainers to fix this, tweak that... :-) For example, it worked well for Boost.GIL (you can PRs at https://github.com/boostorg/gil) "you have to go early even if you go to hell" [2] GSoC IS hard work! Make sure to start early, to take a proactive stance, to do your homework before you start asking questions, to expect no babysitting. Imagine the GSoC runs back in times when there is no StackOverflow, no web archives, no web search,... There really is no excuse for not searching the web first nowadays. Even compilers can do that! https://arxiv.org/abs/1906.11456 "To grow in life, be willing to suffer" ~David Goggins Have a great time during GSoC and good luck! Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[Boost.Python] C++/Python Hybrid App in 2020
by Andrew McFarlane 22 Feb '20

22 Feb '20

Hi all, I read on the Boost.Python FAQ that for Mac OSX users, the library is currently known only to work with the GCC compiler. Thus far, I have been using clang++. I will make the switch, so long that it does increase my odds of encountering difficulties down the road. What do we think here? In the context of front-end dev in Python for a C++ application, is Boost.Python worth making the switch from clang++ to gcc? Would I be better off using something else (i.e. wxPython)? I really love using Boost (I've found use for Test, Signals2, and Asio), but I don't want to let my Boost bias lead me to make a poor choice. I know this question is a tad subjective; I apologize for that. I would like the Python extension to be as seamless as possible, and I am only going to be using Python for front-end code. The interface between the two would likely be with sockets. I am sure I could answer this myself via experimentation, but I wanted to get a feel from the Boost community before doing so. Thanks in advance! *- AJ*

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Newbie Question Shared Memory Containers/Allocators
by Da Xu 14 Feb '20

14 Feb '20

Hi everybody, how are you? I am a completely noob when it comes to Boost. :D But not a noob when it comes to C++. Though, am a bit noobish when it comes to C++14 and beyond :D I am trying to construct a complex data container, which has a vector of floats, on managed shared memory. I followed the documentation, added the appropriate headers and made the following declarations: typedef managed_windows_shared_memory::segment_manager segment_manager_t; typedef allocator<void, segment_manager_t> void_allocator; typedef basic_string<char, std::char_traits<char>, char_allocator> shared_string; typedef allocator<float, segment_manager_t> float_allocator; typedef vector<float, float_allocator> float_vector; typedef allocator<float_vector, segment_manager_t> float_vector_allocator; class ComplexContainer {shared_string name;float_vector channelData; public:ComplexContainer(const char * name_, const float* data_start, const float* data_end, const void_allocator& void_alloc) : name(name_), channelData(data_start, data_end, void_alloc) {} ComplexContainer(const void_allocator& void_alloc) : name(void_alloc), channelData(void_alloc){} ComplexContainer() {} } but I am getting these errors at compile: 1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(310,23): error C2512: 'boost::interprocess::allocator<float,segment_manager_t>::allocator': no appropriate default constructor available1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(308): message : while compiling class template member function 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>::vector_alloc_holder(void) noexcept(false)'1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(832): message : see reference to function template instantiation 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>::vector_alloc_holder(void) noexcept(false)' being compiled1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(779): message : see reference to class template instantiation 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>' being compiled message : see reference to class template instantiation 'boost::container::vector<float,float_allocator,void>' being compiled That doesn't make a whole lot of sense, since it seems to be referring to the "float_allocator" typedef. But float is not an object, it has no constructor. Any help would be greatly appreciated! Thank you! Da.

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Re: [Boost-users] boost float128 and Intel's _Quad with Tux Eigen
by Alex.Durie 04 Feb '20

04 Feb '20

Thanks John, >The good news is that Intel on Linux does support GCC's __float128 type, >so my suggestion would be to: >* Remove the #define BOOST_MP_USE_QUAD >* Build with -std=gnu++14 rather than -std=c++14 >* Remove the -Qoption,cpp,--extended_float_type option. Unfortunately that didn't work, I get the new compiler error; /home/alex/boost/boost_1_71_0/boost/multiprecision/detail/number_base.hpp(216): error: static assertion failed with "is_integral<T>::value || is_enum<T>::value || std::numeric_limits<T>::is_specialized" BOOST_STATIC_ASSERT(is_integral<T>::value || is_enum<T>::value || std::numeric_limits<T>::is_specialized); Are you able to help? Many thanks, Alex ________________________________ From: Boost-users <boost-users-bounces(a)lists.boost.org> on behalf of boost-users-request(a)lists.boost.org <boost-users-request(a)lists.boost.org> Sent: 04 February 2020 10:56 To: boost-users(a)lists.boost.org <boost-users(a)lists.boost.org> Subject: Boost-users Digest, Vol 5318, Issue 1 CAUTION: This mail comes from outside the University. Please consider this before opening attachments, clicking links, or acting on the content. Send Boost-users mailing list submissions to boost-users(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.boost.org/mailman/listinfo.cgi/boost-users or, via email, send a message with subject or body 'help' to boost-users-request(a)lists.boost.org You can reach the person managing the list at boost-users-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." Today's Topics: 1. boost float128 and Intel's _Quad with Tux Eigen (Alex.Durie) 2. [boost build] - How to create symbols (.pdb) files on windows using VS2017 Community Edition? (Eko palypse) 3. Re: [boost build] - How to create symbols (.pdb) files on windows using VS2017 Community Edition? (Mateusz Loskot) 4. Re: [boost build] - How to create symbols (.pdb) files on windows using VS2017 Community Edition? (Eko palypse) 5. Re: boost float128 and Intel's _Quad with Tux Eigen (John Maddock) ---------------------------------------------------------------------- Message: 1 Date: Mon, 3 Feb 2020 21:33:13 +0000 From: Alex.Durie <alex.durie(a)open.ac.uk> To: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> Subject: [Boost-users] boost float128 and Intel's _Quad with Tux Eigen Message-ID: <CWLP265MB0244A9FE67071B7EE7C7E2BFA3000(a)CWLP265MB0244.GBRP265.PROD.OUTLOOK.COM> Content-Type: text/plain; charset="iso-8859-1" Hi, I have written a short program utilising boost::float128 together with tux Eigen which successfully compiles and runs using g++, however it fails when I use icc. The compiler error is /home/alex/boost/boost_1_71_0/boost/multiprecision/float128.hpp(727): error: no suitable constructor exists to convert from "const _Quad" to "boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>" static number_type (min)() BOOST_NOEXCEPT { return BOOST_MP_QUAD_MIN; } ^ How can I resolve this? My example code is; #include <iostream> #include <cmath> #include <Eigen/Dense> #include <Eigen/Eigenvalues> #include <iomanip> #include <boost/cstdfloat.hpp> #include <boost/multiprecision/float128.hpp> #include <boost/math/special_functions.hpp> #include <boost/math/constants/constants.hpp> #include <quadmath.h> #define BOOST_MP_USE_QUAD using namespace Eigen; using namespace std; int main(){ typedef Matrix<complex<boost::multiprecision::float128>, Dynamic, Dynamic> MatrixXcmp; MatrixXcmp C = MatrixXcmp::Random(8,8); cout<<setprecision(128)<<C<<endl<<endl; ComplexEigenSolver<MatrixXcmp> ces; ces.compute(C); return 0; } It only fails compilation when I put in the line 'ces.compute(C);'. I compile with icpc quadtest.cpp -std=c++14 -Qoption,cpp,--extended_float_type -O2 -DMKL_LP64 -lmkl_intel_lp64 -fp-model precise -lmkl_sequential -lmkl_core -lpthread -lm -ldl -lquadmath Many thanks in advance, Alex

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boost float128 and Intel's _Quad with Tux Eigen
by Alex.Durie 04 Feb '20

04 Feb '20

Hi, I have written a short program utilising boost::float128 together with tux Eigen which successfully compiles and runs using g++, however it fails when I use icc. The compiler error is /home/alex/boost/boost_1_71_0/boost/multiprecision/float128.hpp(727): error: no suitable constructor exists to convert from "const _Quad" to "boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>" static number_type (min)() BOOST_NOEXCEPT { return BOOST_MP_QUAD_MIN; } ^ How can I resolve this? My example code is; #include <iostream> #include <cmath> #include <Eigen/Dense> #include <Eigen/Eigenvalues> #include <iomanip> #include <boost/cstdfloat.hpp> #include <boost/multiprecision/float128.hpp> #include <boost/math/special_functions.hpp> #include <boost/math/constants/constants.hpp> #include <quadmath.h> #define BOOST_MP_USE_QUAD using namespace Eigen; using namespace std; int main(){ typedef Matrix<complex<boost::multiprecision::float128>, Dynamic, Dynamic> MatrixXcmp; MatrixXcmp C = MatrixXcmp::Random(8,8); cout<<setprecision(128)<<C<<endl<<endl; ComplexEigenSolver<MatrixXcmp> ces; ces.compute(C); return 0; } It only fails compilation when I put in the line 'ces.compute(C);'. I compile with icpc quadtest.cpp -std=c++14 -Qoption,cpp,--extended_float_type -O2 -DMKL_LP64 -lmkl_intel_lp64 -fp-model precise -lmkl_sequential -lmkl_core -lpthread -lm -ldl -lquadmath Many thanks in advance, Alex

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[boost build] - How to create symbols (.pdb) files on windows using VS2017 Community Edition?
by Eko palypse 03 Feb '20

03 Feb '20

How can I build pdb files using b2 tool? If I run b2 -a --with-regex toolset=msvc-14.1 debug-symbols=on address-model=64 architecture=ia64 variant=debug it creates the needed lib but no pdb files are created. Thank you Eren

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