136 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9// UNSUPPORTED: c++03, c++11, c++14, c++1710 11// <numeric>12 13// template <class _Float>14// _Tp midpoint(_Float __a, _Float __b) noexcept15//16 17#include <limits>18#include <numeric>19#include <cassert>20 21#include "test_macros.h"22#include "fp_compare.h"23 24// Totally arbitrary picks for precision25template <typename T>26constexpr T fp_error_pct();27 28template <>29constexpr float fp_error_pct<float>() { return 1.0e-4f; }30 31template <>32constexpr double fp_error_pct<double>() { return 1.0e-12; }33 34template <>35constexpr long double fp_error_pct<long double>() { return 1.0e-13l; }36 37 38template <typename T>39void fp_test()40{41 ASSERT_SAME_TYPE(T, decltype(std::midpoint(T(), T())));42 ASSERT_NOEXCEPT( std::midpoint(T(), T()));43 44 constexpr T maxV = std::numeric_limits<T>::max();45 constexpr T minV = std::numeric_limits<T>::min();46 47// Things that can be compared exactly48 static_assert((std::midpoint(T(0), T(0)) == T(0)), "");49 static_assert((std::midpoint(T(2), T(4)) == T(3)), "");50 static_assert((std::midpoint(T(4), T(2)) == T(3)), "");51 static_assert((std::midpoint(T(3), T(4)) == T(3.5)), "");52 static_assert((std::midpoint(T(0), T(0.4)) == T(0.2)), "");53 54// Things that can't be compared exactly55 constexpr T pct = fp_error_pct<T>();56 assert((fptest_close_pct(std::midpoint(T( 1.3), T(11.4)), T( 6.35), pct)));57 assert((fptest_close_pct(std::midpoint(T(11.33), T(31.45)), T(21.39), pct)));58 assert((fptest_close_pct(std::midpoint(T(-1.3), T(11.4)), T( 5.05), pct)));59 assert((fptest_close_pct(std::midpoint(T(11.4), T(-1.3)), T( 5.05), pct)));60 assert((fptest_close_pct(std::midpoint(T(0.1), T(0.4)), T(0.25), pct)));61 62 assert((fptest_close_pct(std::midpoint(T(11.2345), T(14.5432)), T(12.88885), pct)));63 64// From e to pi65 assert((fptest_close_pct(std::midpoint(T(2.71828182845904523536028747135266249775724709369995),66 T(3.14159265358979323846264338327950288419716939937510)),67 T(2.92993724102441923691146542731608269097720824653752), pct)));68 69 assert((fptest_close_pct(std::midpoint(maxV, T(0)), maxV/2, pct)));70 assert((fptest_close_pct(std::midpoint(T(0), maxV), maxV/2, pct)));71 assert((fptest_close_pct(std::midpoint(minV, T(0)), minV/2, pct)));72 assert((fptest_close_pct(std::midpoint(T(0), minV), minV/2, pct)));73 assert((fptest_close_pct(std::midpoint(maxV, maxV), maxV, pct)));74 assert((fptest_close_pct(std::midpoint(minV, minV), minV, pct)));75 assert((fptest_close_pct(std::midpoint(maxV, minV), maxV/2, pct)));76 assert((fptest_close_pct(std::midpoint(minV, maxV), maxV/2, pct)));77 78// Near the min and the max79 assert((fptest_close_pct(std::midpoint(maxV*T(0.75), maxV*T(0.50)), maxV*T(0.625), pct)));80 assert((fptest_close_pct(std::midpoint(maxV*T(0.50), maxV*T(0.75)), maxV*T(0.625), pct)));81 assert((fptest_close_pct(std::midpoint(minV*T(2), minV*T(8)), minV*T(5), pct)));82 83// Big numbers of different signs84 assert((fptest_close_pct(std::midpoint(maxV*T( 0.75), maxV*T(-0.5)), maxV*T( 0.125), pct)));85 assert((fptest_close_pct(std::midpoint(maxV*T(-0.75), maxV*T( 0.5)), maxV*T(-0.125), pct)));86 87// Denormalized values88// TODO89 90// Check two values "close to each other"91 T d1 = T(3.14);92 T d0 = std::nextafter(d1, T(2));93 T d2 = std::nextafter(d1, T(5));94 assert(d0 < d1); // sanity checking95 assert(d1 < d2); // sanity checking96 97#if defined(__PPC__) && (defined(__LONG_DOUBLE_128__) && __LONG_DOUBLE_128__) && \98 !(defined(__LONG_DOUBLE_IEEE128__) && __LONG_DOUBLE_IEEE128__)99// For 128 bit long double implemented as 2 doubles on PowerPC,100// nextafterl() of libm gives imprecise results which fails the101// midpoint() tests below. So skip the test for this case.102 if constexpr (sizeof(T) != 16)103#endif104 {105 // Since there's nothing in between, the midpoint has to be one or the other106 T res;107 res = std::midpoint(d0, d1);108 assert(res == d0 || res == d1);109 assert(d0 <= res);110 assert(res <= d1);111 res = std::midpoint(d1, d0);112 assert(res == d0 || res == d1);113 assert(d0 <= res);114 assert(res <= d1);115 116 res = std::midpoint(d1, d2);117 assert(res == d1 || res == d2);118 assert(d1 <= res);119 assert(res <= d2);120 res = std::midpoint(d2, d1);121 assert(res == d1 || res == d2);122 assert(d1 <= res);123 assert(res <= d2);124 }125}126 127 128int main (int, char**)129{130 fp_test<float>();131 fp_test<double>();132 fp_test<long double>();133 134 return 0;135}136