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Boost multiprecision as array index
by Claudio La Rosa 03 Aug '21

03 Aug '21

Hi to all, I unsuccessfully tried to use a boost multiprecision variable (object?) as index of an array. Int myArray[100]; uint128_t index = 23; int value = myArray[index]; This code don’t work. There is a way for to use a multiprecision as index of an array? Thanks. Claudio La Rosa

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[Boost.Json] Loss of precision during serialization/parsing plain double ?
by Marc Viala 03 Aug '21

03 Aug '21

Hello Boost users, I'm starting to implement some serialization tools with Boost.Json but I've got some precision issues with double values. To demonstrate this "potential" issue, you will find here after a code snippet to reproduce it: #include <boost/json.hpp> BOOST_AUTO_TEST_CASE(bjson_double_serialize_ut) { namespace bjs = boost::json; static double ref_values[] = { 1217.2772861138403 , -161.68713249779881 , 267.04251495962637}; std::string s; { const bjs::value jv = { ref_values[0] , ref_values[1], ref_values[2], 0.0, 0.0, 0.0}; s = serialize(jv); } double values[3] = {}; { const auto jv{bjs::parse(s)}; values[0] = jv.as_array().at(0).as_double(); values[1] = jv.as_array().at(1).as_double(); values[2] = jv.as_array().at(2).as_double(); } static constexpr auto eps{std::numeric_limits<double>::epsilon()}; BOOST_TEST(std::abs(ref_values[0] - values[0]) <= eps); BOOST_TEST(std::abs(ref_values[1] - values[1]) <= eps); BOOST_TEST(std::abs(ref_values[2] - values[2]) <= eps); } When I compiling and running this code w/ Boost 1.75 and Microsoft Visual C++ version 14.2 (VS 2019) / Windows 10, I've got the following output: "bjson_double_serialize_ut": check std::abs(ref_values[0] - values[0]) <= eps has failed [2.2737367544323206e-13 > 2.2204460492503131e-16] "bjson_double_serialize_ut": check std::abs(ref_values[2] - values[2]) <= eps has failed [5.6843418860808015e-14 > 2.2204460492503131e-16] >From my point of view, I'm expecting to get a tolerance equal or inf. to my "double machine epsilon". Is this correct and how can I address it ? Marc -- Marc Viala

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UUID
by Ming Cheng 30 Jul '21

30 Jul '21

I have a UUID requirement as: * Each session will also be represented with a Universally Unique ID (UUID), which should be a current timestamp * a unique UUID value set by the customer as a 64-bit value. CME Group recommends using the system timestamp which represents the number of microseconds since epoch (Jan 1, 1970) as the timestamp. * I also need to save it in a Linux file and rebuild the UUID from the saved value. Wondering whether boost UUID code can support it? I checked online document and seems to me quite difficulty except archiving.

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g++ linking error with lboost_program_options
by Stefano Gragnani 27 Jul '21

27 Jul '21

The development system is: MacBook Pro Intel i9 MacOS Big Sur 11.4 gcc version 11.1.0 (Homebrew GCC 11.1.0_1) clang version 12.0.0 I'm having trouble compiling some examples from the book 'Boost C ++ Application Development Cookbook’. The problem occurs only with g ++, with clang there is no error. Mistakes only occur when linking to -lboost_program_options, -lboost_system and -lboost_filesystem, with any other library (eg -lboost_chrono) everything is fine. Furthermore, it should be noted that by linking with -lboost_system and -lboost_filesystem no compilation / linking errors are obtained but we get a SEGMENTATION FAULT (ONLY when compiling with g++, compiling with Clang the program run fine), instead linking with -lboost_program_options results in linking errors. This is the example: #include <boost/program_options.hpp> #include <iostream> namespace opt = boost::program_options; int main(int argc, char *argv[]) { // Constructing an options describing variable and giving it a // textual description "All options" opt::options_description desc("All options"); // When we are adding options, first parameter is a name // to be used in command line. Second parameter is a type // of that option, wrapped in value<> class. Third parameter // must be a short description of that option. desc.add_options() ("apples", opt::value<int>(), "how many apples do you have") ("oranges", opt::value<int>(), "how many oranges do you have") ("help", "produce help message") ; // Variable to store our command line arguments opt::variables_map vm; // Parsing and storing arguments opt::store(opt::parse_command_line(argc, argv, desc), vm); // Must be called after all the parsing and storing opt::notify(vm); if (vm.count("help")) { std::cout << desc << "\n"; return 1; } std::cout << "Fruits count: " << vm["apples"].as<int>() + vm["oranges"].as<int>() << std::endl; } and these are the errors: Undefined symbols for architecture x86_64: "__ZN5boost15program_options11to_internalERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from: __ZN5boost15program_options11to_internalINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEESt6vectorIS7_SaIS7_EERKS8_IT_SaISB_EE in ccmlvHtI.o "__ZN5boost15program_options16validation_error12get_templateB5cxx11ENS1_6kind_tE", referenced from: __ZN5boost15program_options16validation_errorC1ENS1_6kind_tERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_i in ccmlvHtI.o "__ZN5boost15program_options19options_descriptionC1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEjj", referenced from: _main in ccmlvHtI.o "__ZN5boost15program_options20invalid_option_valueC1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from: __ZN5boost15program_options8validateIicEEvRNS_3anyERKSt6vectorINSt7__cxx1112basic_stringIT0_St11char_traitsIS7_ESaIS7_EEESaISB_EEPT_l in ccmlvHtI.o "__ZN5boost15program_options22error_with_option_nameC2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES9_S9_i", referenced from: __ZN5boost15program_options16validation_errorC1ENS1_6kind_tERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_i in ccmlvHtI.o "__ZN5boost15program_options3argB5cxx11E", referenced from: __ZNK5boost15program_options11typed_valueIicE4nameB5cxx11Ev in ccmlvHtI.o "__ZN5boost15program_options6detail7cmdline21set_additional_parserENS_9function1ISt4pairINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_ERKSA_EE", referenced from: __ZN5boost15program_options25basic_command_line_parserIcE12extra_parserENS_9function1ISt4pairINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_ERKSA_EE in ccmlvHtI.o "__ZN5boost15program_options6detail7cmdlineC2ERKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS9_EE", referenced from: __ZN5boost15program_options25basic_command_line_parserIcEC1EiPKPKc in ccmlvHtI.o "__ZN5boost15program_optionslsERSoRKNS0_19options_descriptionE", referenced from: _main in ccmlvHtI.o "__ZNK5boost15program_options22abstract_variables_mapixERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from: __ZNK5boost15program_options13variables_mapixERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE in ccmlvHtI.o "__ZNK5boost15program_options22error_with_option_name23substitute_placeholdersERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from: __ZTVN5boost15program_options20invalid_option_valueE in ccmlvHtI.o __ZTVN5boost15program_options16validation_errorE in ccmlvHtI.o __ZTVN5boost10wrapexceptINS_15program_options16validation_errorEEE in ccmlvHtI.o __ZTVN5boost10wrapexceptINS_15program_options20invalid_option_valueEEE in ccmlvHtI.o "__ZNK5boost15program_options29value_semantic_codecvt_helperIcE5parseERNS_3anyERKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaISB_EEb", referenced from: __ZTVN5boost15program_options11typed_valueIicEE in ccmlvHtI.o ld: symbol(s) not found for architecture x86_64 collect2: error: ld returned 1 exit status The terminal process "zsh '-c', 'g++-11 -g -I/usr/local/Cellar/boost/1.76.0/include/ -I/usr/local/include/ -L/usr/local/Cellar/boost/1.76.0/lib/ -lboost_program_options -std=gnu++20 Chapter01/01_A_program_options_base/main.cpp -o Chapter01/01_A_program_options_base/main'" terminated with exit code: 1. The compile options are (Visual Studio Code): "label": "Build with g++ 11", "type": "shell", "command": "g++-11", "args": [ "-g", "-I/usr/local/Cellar/boost/1.76.0/include/", "-I/usr/local/include/", "-L/usr/local/Cellar/boost/1.76.0/lib/", "-lboost_program_options", // "-lboost_system", // "-lboost_filesystem", // "-lboost_chrono", "-std=gnu++20", "Chapter01/01_A_program_options_base/main.cpp", // "-L/usr/local/Cellar/gcc/11.1.0_1/lib/gcc/11/", "-o", "Chapter01/01_A_program_options_base/main" ] Thanks Stefano Gragnani

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g++ linking error with lboost_program_options
by Stefano Gragnani 23 Jul '21

23 Jul '21

I have the same problem with boost.regex: Clang compiles correctly and g ++ gives linking errors

1 0

Trouble compiling with float128 data type
by Stefano Gragnani 22 Jul '21

22 Jul '21

Hi, I'm having trouble compiling code that contains float128 data type. I'm using MacOS Big Sur 11.4. Compiler: gcc version 11.1.0 (Homebrew GCC 11.1.0_1) I have no other problems with Boost, the only problem is when I use float128. Please note that I have no problem compiling using libquadmath without using Boost using the __float128 data type. I use Visual Studio Code: "tasks": [ { "label": "Build with g++ 11", "type": "shell", "command": "g++-11", "args": [ "-g", "-I/usr/local/Cellar/boost/1.76.0/include/", "-I/usr/local/include/", "-L/usr/local/Cellar/boost/1.76.0/lib/", "-L/usr/local/Cellar/gcc/11.1.0_1/lib/gcc/11/", "-L/usr/local/Cellar/gmp/6.2.1/lib/", "-L/usr/local/Cellar/mpfr/4.1.0/lib/", "-lmpfr", "-lgmp", "-lquadmath", "-lboost_system", "-lboost_filesystem", "-std=c++20", "'-fext-numeric-literals'", "float128_example.cpp", "-o", "main" ], "group": { "kind": "build", "isDefault": true } }, There are other libraries (gmp, mpfr, ...) because I have compiled several examples taken from the Boost site (such as, for example, automatic_differentation.cpp, GMP_example.cpp, MPFR_example.cpp etc.) and they all compile and run correctly. I tried to compile the following example: #include <boost/cstdfloat.hpp> // For float_64_t, float128_t. Must be first include! //#include <boost/config.hpp> #include <boost/multiprecision/float128.hpp> #include <boost/math/special_functions.hpp> // For gamma function. #include <boost/math/constants/constants.hpp> // For constants pi, e ... #include <typeinfo> // #include <cmath> // for pow function. int main() { try { //[float128_example_3 // Always use try'n'catch blocks to ensure any error messages are displayed. //`Ensure that all possibly significant digits (17) including trailing zeros are shown. std::cout.precision(std::numeric_limits<boost::float64_t>::max_digits10); std::cout.setf(std::ios::showpoint); // Show all significant trailing zeros. //] [/ float128_example_3] #ifdef BOOST_FLOAT128_C std::cout << "Floating-point type boost::float128_t is available." << std::endl; std::cout << " std::numeric_limits<boost::float128_t>::digits10 == " << std::numeric_limits<boost::float128_t>::digits10 << std::endl; std::cout << " std::numeric_limits<boost::float128_t>::max_digits10 == " << std::numeric_limits<boost::float128_t>::max_digits10 << std::endl; #else std::cout << "Floating-point type boost::float128_t is NOT available." << std::endl; #endif show_versions(""); using boost::multiprecision::float128; // Wraps, for example, __float128 or _Quad. // or //using namespace boost::multiprecision; std::cout.precision(std::numeric_limits<float128>::max_digits10); // Show all potentially meaningful digits. std::cout.setf(std::ios::showpoint); // Show all significant trailing zeros. // float128 pi0 = boost::math::constants::pi(); // Compile fails - need to specify a type for the constant! float128 pi1 = boost::math::constants::pi<float128>(); // Returns a constant of type float128. std::cout << sqrt(pi1) << std::endl; // 1.77245385090551602729816748334114514 float128 pi2 = boost::math::constants::pi<__float128>(); // Constant of type __float128 gets converted to float128 on the assignment. std::cout << sqrt(pi2) << std::endl; // 1.77245385090551602729816748334114514 // DIY decimal digit literal constant, with suffix Q. float128 pi3 = 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348Q; std::cout << sqrt(pi3) << std::endl; // 1.77245385090551602729816748334114514 // Compare to ready-rolled sqrt(pi) constant from Boost.Math: std::cout << boost::math::constants::root_pi<float128>() << std::endl; // 1.77245385090551602729816748334114514 // DIY decimal digit literal constant, without suffix Q, suffering seventeen silent digits loss of precision! float128 pi4 = 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348; std::cout << sqrt(pi4) << std::endl; // 1.77245385090551599275151910313924857 … … what i get is: > Executing task: g++-11 -g -I/usr/local/Cellar/boost/1.76.0/include/ -I/usr/local/include/ -L/usr/local/Cellar/boost/1.76.0/lib/ -L/usr/local/Cellar/gcc/11.1.0_1/lib/gcc/11/ -L/usr/local/Cellar/gmp/6.2.1/lib/ -L/usr/local/Cellar/mpfr/4.1.0/lib/ -lmpfr -lgmp -lquadmath -lboost_system -lboost_filesystem -std=c++20 '-fext-numeric-literals' float128_example.cpp -o main < float128_example.cpp: In function 'int main()': float128_example.cpp:143:56: error: conversion from 'boost::math::constants::detail::constant_return<__float128, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> >::type' {aka '__float128'} to non-scalar type 'boost::multiprecision::float128' {aka 'boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>'} requested 143 | float128 pi2 = boost::math::constants::pi<__float128>(); // Constant of type __float128 gets converted to float128 on the assignment. | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~ float128_example.cpp:147:18: error: conversion from '__float128' to non-scalar type 'boost::multiprecision::float128' {aka 'boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>'} requested 147 | float128 pi3 = 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348Q; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ float128_example.cpp:160:37: error: conversion from '__float128' to non-scalar type 'const float128' {aka 'const boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>'} requested 160 | constexpr float128 pi_constexpr = 3.1415926535897932384626433832795028841971693993751058Q; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /usr/local/Cellar/boost/1.76.0/include/boost/math/special_functions/gamma.hpp:23, from /usr/local/Cellar/boost/1.76.0/include/boost/math/special_functions/detail/bessel_jy.hpp:14, from /usr/local/Cellar/boost/1.76.0/include/boost/math/special_functions/bessel.hpp:20, from /usr/local/Cellar/boost/1.76.0/include/boost/math/special_functions/airy.hpp:12, from /usr/local/Cellar/boost/1.76.0/include/boost/math/special_functions.hpp:15, from float128_example.cpp:22: float128_example.cpp:172:83: in 'constexpr' expansion of 'boost::math::constants::root_pi<boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off> >()' /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:237:54: error: 'constexpr typename boost::math::constants::detail::constant_return<Real, Policy>::type boost::math::constants::root_pi() [with T = boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>; Policy = boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy>; typename boost::math::constants::detail::constant_return<Real, Policy>::type = const boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>&]' called in a constant expression 237 | { return name<T, boost::math::policies::policy<> >(); }\ | ^ /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:269:3: note: in expansion of macro 'BOOST_DEFINE_MATH_CONSTANT' 269 | BOOST_DEFINE_MATH_CONSTANT(root_pi, 1.772453850905516027298167483341145182e+00, "1.77245385090551602729816748334114518279754945612238712821380778985291128459103218137495065673854466541622682362e+00") | ^~~~~~~~~~~~~~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:269:30: note: 'constexpr typename boost::math::constants::detail::constant_return<Real, Policy>::type boost::math::constants::root_pi() [with T = boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>; Policy = boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy>; typename boost::math::constants::detail::constant_return<Real, Policy>::type = const boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>&]' is not usable as a 'constexpr' function because: 269 | BOOST_DEFINE_MATH_CONSTANT(root_pi, 1.772453850905516027298167483341145182e+00, "1.77245385090551602729816748334114518279754945612238712821380778985291128459103218137495065673854466541622682362e+00") | ^~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:234:116: note: in definition of macro 'BOOST_DEFINE_MATH_CONSTANT' 234 | template <typename T, typename Policy> inline BOOST_CONSTEXPR typename detail::constant_return<T, Policy>::type name(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC(T) BOOST_MATH_APPEND_EXPLICIT_TEMPLATE_TYPE_SPEC(Policy)) BOOST_MATH_NOEXCEPT(T)\ | ^~~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:235:57: error: call to non-'constexpr' function 'static const T& boost::math::constants::detail::constant_root_pi<T>::get(const std::integral_constant<int, 4>&) [with T = boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>]' 235 | { return detail:: BOOST_JOIN(constant_, name)<T>::get(typename construction_traits<T, Policy>::type()); }\ | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:269:3: note: in expansion of macro 'BOOST_DEFINE_MATH_CONSTANT' 269 | BOOST_DEFINE_MATH_CONSTANT(root_pi, 1.772453850905516027298167483341145182e+00, "1.77245385090551602729816748334114518279754945612238712821380778985291128459103218137495065673854466541622682362e+00") | ^~~~~~~~~~~~~~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:207:27: note: 'static const T& boost::math::constants::detail::constant_root_pi<T>::get(const std::integral_constant<int, 4>&) [with T = boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>]' declared here 207 | static inline const T& get(const std::integral_constant<int, construct_from_string>&)\ | ^~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:207:27: note: in definition of macro 'BOOST_DEFINE_MATH_CONSTANT' 207 | static inline const T& get(const std::integral_constant<int, construct_from_string>&)\ | ^~~ float128_example.cpp:186:20: error: call of overloaded 'exp(__float128)' is ambiguous 186 | float128 e1 = exp(1.Q); // Note argument to exp is type float128. | ~~~^~~~~ In file included from /usr/local/Cellar/gcc/11.1.0_1/include/c++/11.1.0/cmath:45, from /usr/local/Cellar/boost/1.76.0/include/boost/config/no_tr1/cmath.hpp:21, from /usr/local/Cellar/boost/1.76.0/include/boost/math/tools/config.hpp:19, from /usr/local/Cellar/boost/1.76.0/include/boost/math/cstdfloat/cstdfloat_types.hpp:18, from /usr/local/Cellar/boost/1.76.0/include/boost/cstdfloat.hpp:18, from float128_example.cpp:19: /usr/local/Cellar/gcc/11.1.0_1/lib/gcc/11/gcc/x86_64-apple-darwin20/11.1.0/include-fixed/math.h:376:15: note: candidate: 'double exp(double)' 376 | extern double exp(double); | ^~~ In file included from /usr/local/Cellar/boost/1.76.0/include/boost/config/no_tr1/cmath.hpp:21, from /usr/local/Cellar/boost/1.76.0/include/boost/math/tools/config.hpp:19, from /usr/local/Cellar/boost/1.76.0/include/boost/math/cstdfloat/cstdfloat_types.hpp:18, from /usr/local/Cellar/boost/1.76.0/include/boost/cstdfloat.hpp:18, from float128_example.cpp:19: /usr/local/Cellar/gcc/11.1.0_1/include/c++/11.1.0/cmath:226:3: note: candidate: 'constexpr long double std::exp(long double)' 226 | exp(long double __x) | ^~~ /usr/local/Cellar/gcc/11.1.0_1/include/c++/11.1.0/cmath:222:3: note: candidate: 'constexpr float std::exp(float)' 222 | exp(float __x) | ^~~ In file included from /usr/local/Cellar/boost/1.76.0/include/boost/math/cstdfloat/cstdfloat_types.hpp:17, from /usr/local/Cellar/boost/1.76.0/include/boost/cstdfloat.hpp:18, from float128_example.cpp:19: /usr/local/Cellar/boost/1.76.0/include/boost/math/tools/precision.hpp: In instantiation of 'constexpr int boost::math::tools::digits() [with T = __float128]': /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:259:3: required from 'static const T& boost::math::constants::detail::constant_pi<T>::get_from_variable_precision() [with T = __float128]' /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:259:3: required from 'static T boost::math::constants::detail::constant_pi<T>::get(const std::integral_constant<int, 0>&) [with T = __float128]' /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:259:3: required from 'constexpr typename boost::math::constants::detail::constant_return<Real, Policy>::type boost::math::constants::pi() [with T = __float128; Policy = boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy>; typename boost::math::constants::detail::constant_return<Real, Policy>::type = __float128]' /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:259:3: required from 'constexpr typename boost::math::constants::detail::constant_return<T>::type boost::math::constants::pi() [with T = __float128; typename boost::math::constants::detail::constant_return<T>::type = __float128]' float128_example.cpp:143:56: required from here /usr/local/Cellar/boost/1.76.0/include/boost/math/tools/precision.hpp:44:51: error: static assertion failed: ::std::numeric_limits<T>::is_specialized 44 | BOOST_STATIC_ASSERT( ::std::numeric_limits<T>::is_specialized); | ^~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/static_assert.hpp:70:55: note: in definition of macro 'BOOST_STATIC_ASSERT' 70 | # define BOOST_STATIC_ASSERT( ... ) static_assert(__VA_ARGS__, #__VA_ARGS__) | ^~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/tools/precision.hpp:44:51: note: 'std::__numeric_limits_base::is_specialized' evaluates to false 44 | BOOST_STATIC_ASSERT( ::std::numeric_limits<T>::is_specialized); | ^~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/static_assert.hpp:70:55: note: in definition of macro 'BOOST_STATIC_ASSERT' 70 | # define BOOST_STATIC_ASSERT( ... ) static_assert(__VA_ARGS__, #__VA_ARGS__) | ^~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/tools/precision.hpp:45:62: error: static assertion failed: ::std::numeric_limits<T>::radix == 2 || ::std::numeric_limits<T>::radix == 10 45 | BOOST_STATIC_ASSERT( ::std::numeric_limits<T>::radix == 2 || ::std::numeric_limits<T>::radix == 10); | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/static_assert.hpp:70:55: note: in definition of macro 'BOOST_STATIC_ASSERT' 70 | # define BOOST_STATIC_ASSERT( ... ) static_assert(__VA_ARGS__, #__VA_ARGS__) | ^~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/math/tools/precision.hpp:45:62: note: '((((int)std::__numeric_limits_base::radix) == 2) || (((int)std::__numeric_limits_base::radix) == 10))' evaluates to false 45 | BOOST_STATIC_ASSERT( ::std::numeric_limits<T>::radix == 2 || ::std::numeric_limits<T>::radix == 10); | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/static_assert.hpp:70:55: note: in definition of macro 'BOOST_STATIC_ASSERT' 70 | # define BOOST_STATIC_ASSERT( ... ) static_assert(__VA_ARGS__, #__VA_ARGS__) | ^~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/lexical_cast/detail/converter_lexical.hpp: In instantiation of 'struct boost::detail::deduce_target_char_impl<boost::detail::deduce_character_type_later<__float128> >': /usr/local/Cellar/boost/1.76.0/include/boost/lexical_cast/detail/converter_lexical.hpp:270:89: required from 'struct boost::detail::deduce_target_char<__float128>' /usr/local/Cellar/boost/1.76.0/include/boost/lexical_cast/detail/converter_lexical.hpp:407:92: required from 'struct boost::detail::lexical_cast_stream_traits<const char*, __float128>' /usr/local/Cellar/boost/1.76.0/include/boost/lexical_cast/detail/converter_lexical.hpp:468:15: required from 'struct boost::detail::lexical_converter_impl<__float128, const char*>' /usr/local/Cellar/boost/1.76.0/include/boost/lexical_cast/try_lexical_convert.hpp:201:44: required from 'bool boost::conversion::detail::try_lexical_convert(const Source&, Target&) [with Target = __float128; Source = const char*]' /usr/local/Cellar/boost/1.76.0/include/boost/lexical_cast.hpp:41:60: [ skipping 2 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ] /usr/local/Cellar/boost/1.76.0/include/boost/math/tools/convert_from_string.hpp:43:39: required from 'constexpr typename boost::math::tools::convert_from_string_result<T>::type boost::math::tools::convert_from_string(const char*) [with Real = __float128; typename boost::math::tools::convert_from_string_result<T>::type = __float128]' /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:259:3: required from 'static const T& boost::math::constants::detail::constant_pi<T>::get_from_variable_precision() [with T = __float128]' /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:259:3: required from 'static T boost::math::constants::detail::constant_pi<T>::get(const std::integral_constant<int, 0>&) [with T = __float128]' /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:259:3: required from 'constexpr typename boost::math::constants::detail::constant_return<Real, Policy>::type boost::math::constants::pi() [with T = __float128; Policy = boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy>; typename boost::math::constants::detail::constant_return<Real, Policy>::type = __float128]' /usr/local/Cellar/boost/1.76.0/include/boost/math/constants/constants.hpp:259:3: required from 'constexpr typename boost::math::constants::detail::constant_return<T>::type boost::math::constants::pi() [with T = __float128; typename boost::math::constants::detail::constant_return<T>::type = __float128]' float128_example.cpp:143:56: required from here /usr/local/Cellar/boost/1.76.0/include/boost/lexical_cast/detail/converter_lexical.hpp:243:54: error: static assertion failed: Target type is neither std::istream`able nor std::wistream`able 243 | BOOST_STATIC_ASSERT_MSG((result_t::value || boost::has_right_shift<std::basic_istream<wchar_t>, T >::value), | ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/static_assert.hpp:31:59: note: in definition of macro 'BOOST_STATIC_ASSERT_MSG' 31 | # define BOOST_STATIC_ASSERT_MSG( ... ) static_assert(__VA_ARGS__) | ^~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/lexical_cast/detail/converter_lexical.hpp:243:54: note: '(((bool)boost::integral_constant<bool, false>::value) || ((bool)boost::integral_constant<bool, false>::value))' evaluates to false 243 | BOOST_STATIC_ASSERT_MSG((result_t::value || boost::has_right_shift<std::basic_istream<wchar_t>, T >::value), | ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /usr/local/Cellar/boost/1.76.0/include/boost/static_assert.hpp:31:59: note: in definition of macro 'BOOST_STATIC_ASSERT_MSG' 31 | # define BOOST_STATIC_ASSERT_MSG( ... ) static_assert(__VA_ARGS__) | ^~~~~~~~~~~ The terminal process "zsh '-c', 'g++-11 -g -I/usr/local/Cellar/boost/1.76.0/include/ -I/usr/local/include/ -L/usr/local/Cellar/boost/1.76.0/lib/ -L/usr/local/Cellar/gcc/11.1.0_1/lib/gcc/11/ -L/usr/local/Cellar/gmp/6.2.1/lib/ -L/usr/local/Cellar/mpfr/4.1.0/lib/ -lmpfr -lgmp -lquadmath -lboost_system -lboost_filesystem -std=c++20 '-fext-numeric-literals' float128_example.cpp -o main'" terminated with exit code: 1. Terminal will be reused by tasks, press any key to close it. Thanks Stefano Gragnani Inviato da iPad

2 9

[release] Boost 1.77.0 beta 1 released
by Marshall Clow 14 Jul '21

14 Jul '21

Boost release 1.77.0 beta 1 is now available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.77.0.beta1/source/> The SHA256 checksums are as follows: 1aba2bf9416d71026c9e6bbd10a2b7cfb31b0950baa7ad0861dfb74984d96bd9 boost_1_77_0_b1.zip 55126d149664541ffc9fd1f41b2ec67146d69bdab92e41da4bb8610b755ca9ec boost_1_77_0_b1.7z 1aabe7704e91f4f8d97b81d03ddc21c3396f4b72fc4041f01bfcfc128bac0d73 boost_1_77_0_b1.tar.gz 3d5801790c96d2bc9ed23372c4f9fd963bc2f39fe540e35d7b4fe586ba77dfa7 boost_1_77_0_b1.tar.bz2 For details of what's in the release, see <https://www.boost.org/users/history/version_1_77_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

1 0

geometry: knn search of point to many linestrings?
by Jens Thiele 14 Jul '21

14 Jul '21

Hi, I have lots of linestrings and want to find the k nearest linestrings to some point. Looking at the example /libs/geometry/doc/index/src/examples/rtree/polygons_shared_ptr.cpp I first thought this should be close to the solution and I just could replace the polygons with linestrings. But now I think the nearest query in that example only finds the nearest polygon bounding boxes and not the nearest polygons. Am I correct? If yes, how would one extend that example to find the nearest polygons? Greetings Jens

2 11

[Serialization] Xml serialization extremely slow after upgrade to boost 1.74
by Elizabeta Petreska 14 Jul '21

14 Jul '21

Hi I upgraded my project to use boost 1.74 instead of boost 1.49. After the upgrade serialization time for my project archive is extremely slow. With boost 1.49 my project archive was serialized about 1 to 2 minutes. With boost 1.74 it takes more than 50 minutes (I stopped the process so I do not know the exact time it takes) to do the serialization. I am experiencing this only when doing xml serialization. Binary serialization is good, maybe just one second difference between 1.49 and 1.74. What could be the problem with xml serialization ? Repeatedly stopping and playing the debugger gets me into this function in the call stack: save_start i.e in save(*) where it saves the name of the attribute in the xml archive. and then in save_iterator. basic_xml_oarchive<Archive>::save_start(const char *name) { if(NULL == name) return; // be sure name has no invalid characters std::for_each(name, name + std::strlen(name), detail::XML_name<const char>()); end_preamble(); if(depth > 0){ this->This()->put('\n'); indent(); } ++depth; this->This()->put('<'); this->This()->save(name); (*) pending_preamble = true; indent_next = false; } And then save(name) calls this function template<class InputIterator> void save_iterator(std::wostream &os, InputIterator begin, InputIterator end){ typedef iterators::wchar_from_mb< iterators::xml_escape<InputIterator> > xmbtows; std::copy( xmbtows(begin), xmbtows(end), boost::archive::iterators::ostream_iterator<wchar_t>(os) ); }

1 0

[Boost.Python] Making Python classes and functions available to C++
by Sean Farrow 13 Jul '21

13 Jul '21

Hi all, What is the easiest way of making Python classes and functions available to external C++ applications. The Boost.Python documentation seems to show making C++ classes available to Python, but I can't find anything that shows going the other way. Any help appreciated. Kind regards Sean.

1 0