1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17 10 // <numeric> 11 12 // template <class _Float> 13 // _Tp midpoint(_Float __a, _Float __b) noexcept 14 // 15 16 #include <numeric> 17 #include <cassert> 18 19 #include "test_macros.h" 20 #include "fp_compare.h" 21 22 // Totally arbitrary picks for precision 23 template <typename T> 24 constexpr T fp_error_pct(); 25 26 template <> 27 constexpr float fp_error_pct<float>() { return 1.0e-4f; } 28 29 template <> 30 constexpr double fp_error_pct<double>() { return 1.0e-12; } 31 32 template <> 33 constexpr long double fp_error_pct<long double>() { return 1.0e-13l; } 34 35 36 template <typename T> 37 void fp_test() 38 { 39 ASSERT_SAME_TYPE(T, decltype(std::midpoint(T(), T()))); 40 ASSERT_NOEXCEPT( std::midpoint(T(), T())); 41 42 constexpr T maxV = std::numeric_limits<T>::max(); 43 constexpr T minV = std::numeric_limits<T>::min(); 44 45 // Things that can be compared exactly 46 assert((std::midpoint(T(0), T(0)) == T(0))); 47 assert((std::midpoint(T(2), T(4)) == T(3))); 48 assert((std::midpoint(T(4), T(2)) == T(3))); 49 assert((std::midpoint(T(3), T(4)) == T(3.5))); 50 assert((std::midpoint(T(0), T(0.4)) == T(0.2))); 51 52 // Things that can't be compared exactly 53 constexpr T pct = fp_error_pct<T>(); 54 assert((fptest_close_pct(std::midpoint(T( 1.3), T(11.4)), T( 6.35), pct))); 55 assert((fptest_close_pct(std::midpoint(T(11.33), T(31.45)), T(21.39), pct))); 56 assert((fptest_close_pct(std::midpoint(T(-1.3), T(11.4)), T( 5.05), pct))); 57 assert((fptest_close_pct(std::midpoint(T(11.4), T(-1.3)), T( 5.05), pct))); 58 assert((fptest_close_pct(std::midpoint(T(0.1), T(0.4)), T(0.25), pct))); 59 60 assert((fptest_close_pct(std::midpoint(T(11.2345), T(14.5432)), T(12.88885), pct))); 61 62 // From e to pi 63 assert((fptest_close_pct(std::midpoint(T(2.71828182845904523536028747135266249775724709369995), 64 T(3.14159265358979323846264338327950288419716939937510)), 65 T(2.92993724102441923691146542731608269097720824653752), pct))); 66 67 assert((fptest_close_pct(std::midpoint(maxV, T(0)), maxV/2, pct))); 68 assert((fptest_close_pct(std::midpoint(T(0), maxV), maxV/2, pct))); 69 assert((fptest_close_pct(std::midpoint(minV, T(0)), minV/2, pct))); 70 assert((fptest_close_pct(std::midpoint(T(0), minV), minV/2, pct))); 71 assert((fptest_close_pct(std::midpoint(maxV, maxV), maxV, pct))); 72 assert((fptest_close_pct(std::midpoint(minV, minV), minV, pct))); 73 74 // Denormalized values 75 // TODO 76 77 // Check two values "close to each other" 78 T d1 = 3.14; 79 T d0 = std::nextafter(d1, T(2)); 80 T d2 = std::nextafter(d1, T(5)); 81 assert(d0 < d1); // sanity checking 82 assert(d1 < d2); // sanity checking 83 84 // Since there's nothing in between, the midpoint has to be one or the other 85 T res; 86 res = std::midpoint(d0, d1); 87 assert(res == d0 || res == d1); 88 assert(d0 <= res); 89 assert(res <= d1); 90 res = std::midpoint(d1, d0); 91 assert(res == d0 || res == d1); 92 assert(d0 <= res); 93 assert(res <= d1); 94 95 res = std::midpoint(d1, d2); 96 assert(res == d1 || res == d2); 97 assert(d1 <= res); 98 assert(res <= d2); 99 res = std::midpoint(d2, d1); 100 assert(res == d1 || res == d2); 101 assert(d1 <= res); 102 assert(res <= d2); 103 } 104 105 106 int main (int, char**) 107 { 108 fp_test<float>(); 109 fp_test<double>(); 110 fp_test<long double>(); 111 112 return 0; 113 } 114