- Boost-users - lists.boost.org

Boost geometry: 3d difference and union?
by KL 13 Dec '21

13 Dec '21

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Question on boost shared memory allocators
by Da Xu 08 Dec '21

08 Dec '21

Hi folks, got a couple of questions about using shared memory allocators. Please see below. I have the following code template <typename T> using CAP_Alloc = cached_adaptive_pool<T, segment_manager_t>; using CAP_Shmem_String = basic_string<char, std::char_traits<char>, CAP_Alloc<char> >; using CAP_Shmem_String_Alloc = CAP_Alloc<CAP_Shmem_String>; using CAP_Shmem_Void_Alloc = CAP_Alloc<void>; class MyDataBlock{ using pointer = CAP_Shmem_String_Alloc::pointer; pointer strData; float extraData; MyDataBlock(): strData(nullptr), extraData(0.0) {} MyDataBlock(const CAP_Shmem_Void_Alloc& alloc) { /* My question is how do I convert CAP_Shmem_Void_Alloc to type CAP_Shmem_String_Alloc to call allocate? And do I pass in the void allocator as a construction argument? Is there a difference between allocate and construct? */ } ~MyDataBlock() { /* To delete the memory, do I need to keep around a copy of the original allocator, so I can call deallocate or destroy? Or can that be derived or converted from somewhere, like calling strData->alloc() ? */ } } Any help would be greatly appreciated. Thank you.

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[release] Boost 1.78.0
by Marshall Clow 08 Dec '21

08 Dec '21

Release 1.78.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains numerous enhancements and bug fixes for existing libraries. For details, including download links, see <http://www.boost.org/users/news/version_1.78.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.78.0/> To install this release on your system, see <http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. Thanks, -- The Boost Release Team Marshall Clow, Michael Caisse, Glen Fernandes

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[release] Boost 1.78.0 Release Candidate 1
by Marshall Clow 03 Dec '21

03 Dec '21

The first release candidates for the 1.78.0 release are now available at: <https://boostorg.jfrog.io/artifactory/main/release/1.78.0/source/> The SHA256 checksums are as follows: 94ced8b72956591c4775ae2207a9763d3600b30d9d7446562c552f0a14a63be7 boost_1_78_0_rc1.tar.gz f22143b5528e081123c3c5ed437e92f648fe69748e95fa6e2bd41484e2986cc3 boost_1_78_0_rc1.zip 090cefea470bca990fa3f3ed793d865389426915b37a2a3258524a7258f0790c boost_1_78_0_rc1.7z 8681f175d4bdb26c52222665793eef08490d7758529330f98d3b29dd0735bccc boost_1_78_0_rc1.tar.bz2 As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

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[Graph] Occasional crash when removing a vertex
by Anne van de Graaf 29 Nov '21

29 Nov '21

Hello all, When I remove a vertex from a graph, I occasionally experience a crash (on a system running Red Hat Enterprise Linux 8.5). I have been able to replicate the behavior with the following test program: #include <boost/graph/adjacency_list.hpp> int main() { using MyGraph = boost::adjacency_list<boost::setS, boost::vecS, boost::undirectedS>; using MyVertexDescriptor = boost::graph_traits<MyGraph>::vertex_descriptor; using MyVertexDescriptorVec = std::vector<MyVertexDescriptor>; MyGraph g; MyVertexDescriptorVec vertices{ boost::add_vertex( g ), boost::add_vertex( g ), boost::add_vertex( g ) }; boost::add_edge( vertices[0], vertices[1], g ); boost::add_edge( vertices[1], vertices[2], g ); boost::clear_vertex( vertices[0], g ); boost::remove_vertex( vertices[0], g ); return 0; } Also on a Windows platform, I observe similar behavior. When I build the above code with Microsoft Visual Studio 2019 (MSVC 14.27.29110) and run it with a debugger, a debug assertion is triggered ("cannot increment value-initialized map/set iterator"). In both cases (on Linux and Windows platforms), the debugger reveals that the problem is at line 2071 of boost/graph/detail/adjacency_list.hpp. For clarity, I have copied the involved template function below: template < class EdgeList, class vertex_descriptor > inline void reindex_edge_list( EdgeList& el, vertex_descriptor u, boost::disallow_parallel_edge_tag) { for (typename EdgeList::iterator ei = el.begin(); ei != el.end(); ++ei) // line 2071: increment operator fails { if (ei->get_target() > u) { typename EdgeList::value_type ce = *ei; el.erase(ce); --ce.get_target(); el.insert(ce); } } } While I was searching for a proper place to post my question, I found the following issue at GitHub (which was opened on July 1 of this year): https://github.com/boostorg/graph/issues/268. This appears to be the exact same issue. So last week, I added a comment saying that I am facing the exact same problem. Unfortunately, so far no one has responded yet. To me, it seems that the problem is well-understood. Also, some have proposed a bug fix to resolve the issue (including a pull request). Nevertheless, no progress has been made over the past months. So I was just wondering what is the best way to proceed if we want to fix the issue in Boost itself? Is there anything that I can do (apart from starting this thread) to help in resolving the issue? Any feedback is greatly appreciated. Kind regards, Anne van de Graaf

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assigning a "float128" variable with a regular "double" variable
by Jacques Mequin 27 Nov '21

27 Nov '21

I am a fresh new user ( I need to extend some EIGEN library feature by using your float128 ) How to assign a "float128" variable with a regular "double" variable ? With my source code in attachement double double_pi = 3.141592653589793 ; float128 float128_pi = 3.141592653589793Q ; produces the output that looks fine to me double_pi = 3.141592653589793e+00 float128_pi = 3.141592653589793000000000000000000e+00 but thestatement float128_pi = double_pi ; produces float128_pi = 3.141592653589793115997963468544185e+00 How to get 3.141592653589793000000000000000000e+00 also from an assigment ??? What am I doing wrong ? Thanks for any help Regards, Jacques

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Fw: How to access global fixture class member
by Ming Cheng 21 Nov '21

21 Nov '21

________________________________ From: Ming Cheng Sent: Thursday, November 18, 2021 6:52 AM To: Boost-interest(a)lists.boost.org <Boost-interest(a)lists.boost.org> Subject: How to access global fixture class member Hi struct Myconfig{ int m_any; }; BOOST_GLOBAL_FIXTURE(Myconfig) How to access m_any?

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boost units and single-precision floats
by Carel Combrink 19 Nov '21

19 Nov '21

Hi, I have aliases for radians and degrees that use float as the storage type. When I convert between these two units I see the assembly promote the values to doubles and then back to floats. How can I make sure that all operations and conversions stay in floats? PS: I would not be surprised if I have defined my aliases or/and my conversion functions incorrectly. My Code: === using radians_f = boost::units::quantity<boost::units::si::plane_angle, float>; using degrees_f = boost::units::quantity<boost::units::degree::plane_angle, float>; degrees_f to_degrees(const radians_f& angle) { return static_cast<degrees_f>(angle); } radians_f to_radians(const degrees_f& angle) { return static_cast<radians_f>(angle); } === >From compiler explorer I see the following assembly instructions: https://godbolt.org/z/Gnjr54dn6 cvtss2sd - Converts a single-precision floating-point value in the “convert-from” source operand to a double-precision floating-point value in the destination operand. mulsd - Multiplies the low double-precision floating-point value in the second source operand by the low double-precision floating-point value in the first source operand. cvtsd2ss - Converts a double-precision floating-point value in the “convert-from” source operand to a single-precision floating-point value Any help will be appreciated. Regards, Carel

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Using Boost Compute with ArrayFire
by Muhammad Hassan Khan 17 Nov '21

17 Nov '21

Hi, I am trying to run a code which uses functions from both boost compute library and arrayfire library. I am getting the following errors when I try to build the code: Scanning dependencies of target hello [ 50%] Building CXX object CMakeFiles/hello.dir/hello.cpp.o In file included from /opt/arrayfire/include/CL/cl.h:32, from /usr/include/boost/compute/cl.hpp:19, from /usr/include/boost/compute/system.hpp:20, from /usr/include/boost/compute/algorithm/accumulate.hpp:17, from /usr/include/boost/compute/algorithm.hpp:18, from /usr/include/boost/compute.hpp:14, from /home/rcms/debruijn/arrayfire/hello.cpp:2: /opt/arrayfire/include/CL/cl_version.h:34:104: note: #pragma message: cl_version.h: CL_TARGET_OPENCL_VERSION is not defined. Defaulting to 220 (OpenCL 2.2) 34 | #pragma message("cl_version.h: CL_TARGET_OPENCL_VERSION is not defined. Defaulting to 220 (OpenCL 2.2)") | ^ [100%] Linking CXX executable hello /usr/bin/ld: CMakeFiles/hello.dir/hello.cpp.o: undefined reference to symbol 'clGetDeviceIDs@@OPENCL_1.0' /usr/bin/ld: /opt/arrayfire/lib64/libOpenCL.so.1: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status make[2]: *** [CMakeFiles/hello.dir/build.make:85: hello] Error 1 make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/hello.dir/all] Error 2 make: *** [Makefile:84: all] Error 2 The code I am using is a very simple helloworld using functions from both libraries. #include <iostream> #include <boost/compute.hpp> #include <arrayfire.h> namespace compute = boost::compute; using namespace af; int main() { // Boost Compute Part // get the default device compute::device device = compute::system::default_device(); // print the device's name and platform std::cout << "hello from " << device.name(); std::cout << " (platform: " << device.platform().name() << ")" << std::endl; // Array Fire Part std::cout<< "ArrayFire Part:" << std::endl; af::setDevice(0); af::info(); return 0; } The CMakeList used to build the project is: cmake_minimum_required(VERSION 3.0) project(deBruijn_Graph) find_package(ArrayFire) add_executable(hello hello.cpp) target_link_libraries(hello ArrayFire::afopencl) I do not have a programming background. Please guide me on what I am doing wrong. Regards, Hassan <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campai…> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campai…> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

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pgRouting use BGL
by Vicky Vergara 12 Nov '21

12 Nov '21

Hello, First of all, I want to congratulate you for the amazing job you are doing. I am the main developer of pgRouting, and the project is part of the OSGeo Foundation [2] community projects. pgRouting extends the PostGIS / PostgreSQL geospatial database to provide geospatial routing functionality. I would like pgRouting [1] to be added on the list of "Boost Graph Library Users" The Boost license is on the projects repository [3] and we document when a boost graph function is used for example in [4] [1] https://pgrouting.org/ [2] https://www.osgeo.org [3] https://github.com/pgRouting/pgrouting [4] https://docs.pgrouting.org/latest/en/pgr_aStar.html Thanks Vicky Vergara -- Georepublic UG (haftungsbeschränkt) Salzmannstraße 44, 81739 München, Germany Vicky Vergara Operations Research eMail: vicky(a)georepublic.de Web: https://georepublic.info Tel: +49 (089) 4161 7698-1 Fax: +49 (089) 4161 7698-9 Commercial register: Amtsgericht München, HRB 181428 CEO: Daniel Kastl

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