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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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[release] Boost 1.7.0 beta 1 released
by Marshall Clow 11 Nov '21

11 Nov '21

Boost release 1.77.0 beta 1 is now available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.78.0.beta1/source/> The SHA256 checksums are as follows: 7a3a025451dfa2923129214eef7d16b03c02310a353d02158a549f6caa4284b0 boost_1_78_0_b1.tar.bz2 c491b1dcb916195598aa6581d6708d57fcc750516641c22511c088d572de9c07 boost_1_78_0_b1.tar.gz 35e7a3b0eb412a3933e57c72ba96374eb7d88ff1f89dbec62a16d67ffea2105a boost_1_78_0_b1.7z e6b68feb2f63401c96ca9fe25e939b409189fbe526a6e784e4bd69832c8f09cb boost_1_78_0_b1.zip For details of what's in the release, see <https://www.boost.org/users/history/version_1_78_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

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Boost.asio. Crash in Tutorial Timer.5, "Synchronizing handlers in multithreaded programs"
by Senthil Cheetancheri 11 Nov '21

11 Nov '21

Hi, I'm learning to use Boost.asio by going through the tutorials at [1]. However, the listing for "Synchronizing handlers in multithreaded programs" crashes on my Ubuntu. Source listing (about 70 lines) is at [2]. I have given my compilation steps, stack trace from gdb, and boost information below. Can you please advise how I can get this working right? [1] https://www.boost.org/doc/libs/1_77_0/doc/html/boost_asio/tutorial.html [2] https://www.boost.org/doc/libs/1_77_0/doc/html/boost_asio/tutorial/tuttimer… I compiled and ran as follows: $ g++ -g -o timer_5.1 timer_5.1.cpp -lpthread -lboost_thread $ ./timer_5.1 Timer 1: 0 Timer 2: 1 Timer 1: 2 Timer 2: 3 Timer 1: 4 Timer 2: 5 Timer 1: 6 Timer 2: 7 Timer 1: 8 Timer 2: 9 Segmentation fault (core dumped) The backtrace from gdb is: $ cat gdb_log.txt #0 0x00007ffff799f88b in ?? () from /usr/lib/x86_64-linux-gnu/libboost_thread.so.1.65.1 #1 0x00007ffff79a0bd5 in ?? () from /usr/lib/x86_64-linux-gnu/libboost_thread.so.1.65.1 #2 0x00007ffff7bbb6db in start_thread (arg=0x7ffff6851700) at pthread_create.c:463 #3 0x00007ffff711e71f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 I have the following boost library installed: $ sudo apt show libboost-all-dev Package: libboost-all-dev Version: 1.65.1.0ubuntu1 Priority: optional Section: universe/libdevel Source: boost-defaults Origin: Ubuntu Maintainer: Ubuntu Developers <ubuntu-devel-discuss(a)lists.ubuntu.com> Original-Maintainer: Debian Boost Team <pkg-boost-devel(a)lists.alioth.debian.org> Bugs: https://bugs.launchpad.net/ubuntu/+filebug Installed-Size: 10.2 kB Depends: libboost-dev, libboost-tools-dev, libboost-atomic-dev, libboost-chrono-dev, libboost-container-dev, libboost-context-dev, libboost-coroutine-dev, libboost-date-time-dev, libboost-exception-dev, libboost-fiber-dev, libboost-filesystem-dev, libboost-graph-dev, libboost-graph-parallel-dev, libboost-iostreams-dev, libboost-locale-dev, libboost-log-dev, libboost-math-dev, libboost-mpi-dev, libboost-mpi-python-dev, libboost-numpy-dev, libboost-program-options-dev, libboost-python-dev, libboost-random-dev, libboost-regex-dev, libboost-serialization-dev, libboost-signals-dev, libboost-stacktrace-dev, libboost-system-dev, libboost-test-dev, libboost-thread-dev, libboost-timer-dev, libboost-type-erasure-dev, libboost-wave-dev Homepage: http://www.boost.org/ Download-Size: 2,340 B APT-Manual-Installed: yes . . . Thanks in advance. Thanks, Senthil.

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[release] Boost 1.78.0 Beta 1 Release Candidate 1 is available
by Marshall Clow 09 Nov '21

09 Nov '21

The first release candidates for the 1.78.0 beta release are now available at: <https://boostorg.jfrog.io/ui/native/main/beta/1.78.0.beta1/source <https://boostorg.jfrog.io/ui/native/main/beta/1.78.0.beta1/source>> The SHA256 checksums are as follows: 7a3a025451dfa2923129214eef7d16b03c02310a353d02158a549f6caa4284b0 boost_1_78_0_b1_rc1.tar.bz2 c491b1dcb916195598aa6581d6708d57fcc750516641c22511c088d572de9c07 boost_1_78_0_b1_rc1.tar.gz 35e7a3b0eb412a3933e57c72ba96374eb7d88ff1f89dbec62a16d67ffea2105a boost_1_78_0_b1_rc1.7z e6b68feb2f63401c96ca9fe25e939b409189fbe526a6e784e4bd69832c8f09cb boost_1_78_0_b1_rc1.zip 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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Boost libraries packaged for build2
by Boris Kolpackov 02 Nov '21

02 Nov '21

We have added support for the build2 build systems to 136 out of 145 Boost libraries and version 1.77.0 is now available from the cppget.org package repository. For details, see: https://build2.org/blog/build2-boost.xhtml

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Iterate intrusive list without container?
by John W 24 Oct '21

24 Oct '21

With a traditional "hand-rolled" doubly-linked list, if you have a reference to a Node, you can traverse from that node to the end of the list easily. Just check for "pNext == NULL" to know when you're at the end. You don't need any reference to the owning "list container" object. However, I can't seem to accomplish the same with boost::intrusive::list. Traversal with an intrusive::list's iterator is done STL-style, and for that you need to compare to the container's ".end()" value. I am aware of the "s_iterator_to" function[1], which can statically get an iterator from a node, but there doesn't seem to be any way to statically get a usable ".end()" value to compare to. There is also "container_from_end_iterator"[2], which gives the container if you have "end()" available already — not quite what I want, but I guess shows that end() is intimately tied to the container. I also notice that if I have an iterator to the last element in a list, and I increment it (++iterator), no error is given. But if I try to dereference it, I get garbage data. Peeking into the implementation, from what I can tell, boost::intrusive::list is actually a circular list, with a special "root node" that the container owns, and which represents the "end". So, iterating beyond the end gives you that root node. I guess my questions are: (1) Is my analysis above correct? I feel I might have missed something wading through all the templates, and the docs I've found don't discuss these implementation details. (2) Is there any way to accomplish what I want? That is: iterating from an arbitrary node to the end of the list, *without* a reference to the owning container? (3) [aside] If the answer to the above is "no", does anyone know what the rationale is for this design choice? It seems odd that such a basic feature of a traditional hand-made intrusive list would be dropped if there were no benefit. Thanks -John [1] https://github.com/boostorg/intrusive/blob/f44b0102b4ee9acf7b0304b3f5b27dde… [2] https://github.com/boostorg/intrusive/blob/f44b0102b4ee9acf7b0304b3f5b27dde…

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