/////////////////////////////////////////////////////////////// // Copyright 2013 John Maddock. Distributed under the Boost // Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt // Demonstrations of using Boost.Multiprecision float128 quad type. // (Only available using GCC compiler). // Contains Quickbook markup in comments. //[float128_eg #include #include #include #include int main() { using namespace boost::multiprecision; // Potential to cause name collisions? // using boost::multiprecision::float128; // is safer. /*`The type float128 provides operations at 128-bit precision with [@https://en.wikipedia.org/wiki/Quadruple-precision_floating-point_format#IEEE_754_quadruple-precision_binary_floating-point_format:_binary128 Quadruple-precision floating-point format] and have full `std::numeric_limits` support: */ float128 b = 2; //` There are 15 bits of (biased) binary exponent and 113-bits of significand precision std::cout << std::numeric_limits::digits << std::endl; //` or 33 decimal places: std::cout << std::numeric_limits::digits10 << std::endl; //` We can use any C++ std library function, so let's show all the at-most 36 potentially significant digits, and any trailing zeros, as well: std::cout.setf(std::ios_base::showpoint); // Include any trailing zeros. std::cout << std::setprecision(std::numeric_limits::max_digits10) << log(b) << std::endl; // Shows log(2) = 0.693147180559945309417232121458176575 //` We can also use any function from Boost.Math, for example, the 'true gamma' function `tgamma`: std::cout << boost::math::tgamma(b) << std::endl; /*` And since we have an extended exponent range, we can generate some really large numbers here (4.02387260077093773543702433923004111e+2564): */ std::cout << boost::math::tgamma(float128(1000)) << std::endl; /*` We can declare constants using GCC or Intel's native types, and literals with the Q suffix, and these can be declared `constexpr` if required: */ // std::numeric_limits::max_digits10 = 36 constexpr float128 pi = 3.14159265358979323846264338327950288Q; std::cout.precision(std::numeric_limits::max_digits10); std::cout << "pi = " << pi << std::endl; //pi = 3.14159265358979323846264338327950280 //] [/float128_eg] // Full generation for numeric limits below: using boost::multiprecision::float128; std::cout << std::boolalpha; std::cout << std::setprecision(std::numeric_limits::max_digits10); std::cout << "GCC " << __VERSION__ << std::endl << std::endl; std::cout << "Type name: boost::multiprecision::float128" << std::endl; std::cout << "Full name: " << boost::typeindex::type_id().pretty_name() << std::endl << std::endl; #if defined(__cpp_lib_type_trait_variable_templates) && (__cpp_lib_type_trait_variable_templates >= 201510L) std::cout << "std::is_fundamental<> = " << std::is_fundamental_v << std::endl; std::cout << "boost::multiprecision::detail::is_signed<> = " << boost::multiprecision::detail::is_signed_v << std::endl; std::cout << "boost::multiprecision::detail::is_unsigned<> = " << boost::multiprecision::detail::is_unsigned_v << std::endl; std::cout << "boost::multiprecision::detail::is_integral<> = " << boost::multiprecision::detail::is_integral_v << std::endl; std::cout << "boost::multiprecision::detail::is_arithmetic<> = " << boost::multiprecision::detail::is_arithmetic_v << std::endl; std::cout << "std::is_const<> = " << std::is_const_v << std::endl; std::cout << "std::is_trivial<> = " << std::is_trivial_v << std::endl; std::cout << "std::is_trivially_copyable<> = " << std::is_trivially_copyable_v << std::endl; std::cout << "std::is_standard_layout<> = " << std::is_standard_layout_v << std::endl; std::cout << "std::is_pod<> = " << std::is_pod_v << std::endl; #endif std::cout << "std::numeric_limits<>::is_exact = " << std::numeric_limits::is_exact << std::endl; std::cout << "std::numeric_limits<>::is_bounded = " << std::numeric_limits::is_bounded << std::endl; std::cout << "std::numeric_limits<>::is_modulo = " << std::numeric_limits::is_modulo << std::endl; std::cout << "std::numeric_limits<>::is_iec559 = " << std::numeric_limits::is_iec559 << std::endl; std::cout << "std::numeric_limits<>::traps = " << std::numeric_limits::traps << std::endl; std::cout << "std::numeric_limits<>::tinyness_before = " << std::numeric_limits::tinyness_before << std::endl; std::cout << "std::numeric_limits<>::max() = " << (std::numeric_limits::max)() << std::endl; std::cout << "std::numeric_limits<>::min() = " << (std::numeric_limits::min)() << std::endl; std::cout << "std::numeric_limits<>::lowest() = " << std::numeric_limits::lowest() << std::endl; std::cout << "std::numeric_limits<>::min_exponent = " << std::numeric_limits::min_exponent << std::endl; std::cout << "std::numeric_limits<>::max_exponent = " << std::numeric_limits::max_exponent << std::endl; std::cout << "std::numeric_limits<>::epsilon() = " << std::numeric_limits::epsilon() << std::endl; std::cout << "std::numeric_limits<>::radix = " << std::numeric_limits::radix << std::endl; std::cout << "std::numeric_limits<>::digits = " << std::numeric_limits::digits << std::endl; std::cout << "std::numeric_limits<>::max_digits10 = " << std::numeric_limits::max_digits10 << std::endl; std::cout << "std::numeric_limits<>::has_denorm = " << std::numeric_limits::has_denorm << std::endl; std::cout << "std::numeric_limits<>::denorm_min() = " << std::numeric_limits::denorm_min() << std::endl; std::cout << "std::numeric_limits<>::has_denorm_loss = " << std::numeric_limits::has_denorm_loss << std::endl; std::cout << "std::numeric_limits<>::has_signaling_NaN = " << std::numeric_limits::has_signaling_NaN << std::endl; std::cout << "std::numeric_limits<>::quiet_NaN() = " << std::numeric_limits::quiet_NaN() << std::endl; std::cout << "std::numeric_limits<>::infinity() = " << std::numeric_limits::infinity() << std::endl; return 0; } /* //[float128_numeric_limits GCC 14.1.0 Type name: boost::multiprecision::float128 Full name: boost::multiprecision::number std::is_fundamental<> = false boost::multiprecision::detail::is_signed<> = false boost::multiprecision::detail::is_unsigned<> = false boost::multiprecision::detail::is_integral<> = false boost::multiprecision::detail::is_arithmetic<> = false std::is_const<> = false std::is_trivial<> = false std::is_trivially_copyable<> = true std::is_standard_layout<> = true std::is_pod<> = false std::numeric_limits<>::is_exact = false std::numeric_limits<>::is_bounded = true std::numeric_limits<>::is_modulo = false std::numeric_limits<>::is_iec559 = true std::numeric_limits<>::traps = false std::numeric_limits<>::tinyness_before = false std::numeric_limits<>::max() = 1.18973149535723176508575932662800702e+4932 std::numeric_limits<>::min() = 3.3621031431120935062626778173217526e-4932 std::numeric_limits<>::lowest() = -1.18973149535723176508575932662800702e+4932 std::numeric_limits<>::min_exponent = -16381 std::numeric_limits<>::max_exponent = 16384 std::numeric_limits<>::epsilon() = 1.92592994438723585305597794258492732e-34 std::numeric_limits<>::radix = 2 std::numeric_limits<>::digits = 113 std::numeric_limits<>::max_digits10 = 36 std::numeric_limits<>::has_denorm = 1 std::numeric_limits<>::denorm_min() = 6.47517511943802511092443895822764655e-4966 std::numeric_limits<>::has_denorm_loss = true std::numeric_limits<>::has_signaling_NaN = false std::numeric_limits<>::quiet_NaN() = nan std::numeric_limits<>::infinity() = inf //] [/float128_numeric_limits] */