1 /////////////////////////////////////////////////////////////// 2 // Copyright 2013 Christopher Kormanyos. Distributed under the Boost 3 // Software License, Version 1.0. (See accompanying file 4 // LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt 5 // 6 7 // Test case for ticket: 8 // #8065: Multiprecision rounding issue 9 10 #ifdef _MSC_VER 11 #define _SCL_SECURE_NO_WARNINGS 12 #endif 13 14 #include <boost/detail/lightweight_test.hpp> 15 #include "test.hpp" 16 #include <boost/multiprecision/cpp_dec_float.hpp> 17 #include <boost/math/special_functions/round.hpp> 18 19 template <int N> round_test_imp()20static bool round_test_imp() 21 { 22 typedef boost::multiprecision::cpp_dec_float<N> mp_backend_type; 23 typedef boost::multiprecision::number<mp_backend_type, boost::multiprecision::et_off> mp_type; 24 25 const mp_type original_digits(1.0F); 26 27 const mp_type scale = pow(mp_type(10), N); 28 29 mp_type these_digits = original_digits * scale; 30 31 these_digits = boost::math::round(these_digits); 32 these_digits /= scale; 33 34 const std::string result = these_digits.str(); 35 36 return (result == original_digits.str()); 37 } 38 39 template <int N> 40 struct round_test 41 { testround_test42 static bool test() 43 { 44 return (round_test_imp<N>() && round_test<N - 1>::test()); 45 } 46 }; 47 48 template <> 49 struct round_test<0> 50 { testround_test51 static bool test() 52 { 53 return round_test_imp<0>(); 54 } 55 }; 56 main()57int main() 58 { 59 // 60 // Test cpp_dec_float rounding with boost::math::round() at various precisions: 61 // 62 const bool round_test_result = round_test<40>::test(); 63 64 BOOST_CHECK_EQUAL(round_test_result, true); 65 66 return boost::report_errors(); 67 } 68