Michal Gorny 87ae6bf80b [libc++] [test] Use std::nextafter() instead of std::nexttoward()
Use std::nextafter() instead of std::nexttoward() in midpoint tests.
In the context of this test, this should not cause any difference.
Since nexttowardl() is not implemented on NetBSD 8, the latter function
combined with 'long double' type caused test failure.  nextafterl() does
not have this problem.

Differential Revision: https://reviews.llvm.org/D61748

llvm-svn: 360673
2019-05-14 13:56:20 +00:00

114 lines
3.7 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
// <numeric>
// template <class _Float>
// _Tp midpoint(_Float __a, _Float __b) noexcept
//
#include <numeric>
#include <cassert>
#include "test_macros.h"
#include "fp_compare.h"
// Totally arbitrary picks for precision
template <typename T>
constexpr T fp_error_pct();
template <>
constexpr float fp_error_pct<float>() { return 1.0e-4f; }
template <>
constexpr double fp_error_pct<double>() { return 1.0e-12; }
template <>
constexpr long double fp_error_pct<long double>() { return 1.0e-13l; }
template <typename T>
void fp_test()
{
ASSERT_SAME_TYPE(T, decltype(std::midpoint(T(), T())));
ASSERT_NOEXCEPT( std::midpoint(T(), T()));
constexpr T maxV = std::numeric_limits<T>::max();
constexpr T minV = std::numeric_limits<T>::min();
// Things that can be compared exactly
assert((std::midpoint(T(0), T(0)) == T(0)));
assert((std::midpoint(T(2), T(4)) == T(3)));
assert((std::midpoint(T(4), T(2)) == T(3)));
assert((std::midpoint(T(3), T(4)) == T(3.5)));
assert((std::midpoint(T(0), T(0.4)) == T(0.2)));
// Things that can't be compared exactly
constexpr T pct = fp_error_pct<T>();
assert((fptest_close_pct(std::midpoint(T( 1.3), T(11.4)), T( 6.35), pct)));
assert((fptest_close_pct(std::midpoint(T(11.33), T(31.45)), T(21.39), pct)));
assert((fptest_close_pct(std::midpoint(T(-1.3), T(11.4)), T( 5.05), pct)));
assert((fptest_close_pct(std::midpoint(T(11.4), T(-1.3)), T( 5.05), pct)));
assert((fptest_close_pct(std::midpoint(T(0.1), T(0.4)), T(0.25), pct)));
assert((fptest_close_pct(std::midpoint(T(11.2345), T(14.5432)), T(12.88885), pct)));
// From e to pi
assert((fptest_close_pct(std::midpoint(T(2.71828182845904523536028747135266249775724709369995),
T(3.14159265358979323846264338327950288419716939937510)),
T(2.92993724102441923691146542731608269097720824653752), pct)));
assert((fptest_close_pct(std::midpoint(maxV, T(0)), maxV/2, pct)));
assert((fptest_close_pct(std::midpoint(T(0), maxV), maxV/2, pct)));
assert((fptest_close_pct(std::midpoint(minV, T(0)), minV/2, pct)));
assert((fptest_close_pct(std::midpoint(T(0), minV), minV/2, pct)));
assert((fptest_close_pct(std::midpoint(maxV, maxV), maxV, pct)));
assert((fptest_close_pct(std::midpoint(minV, minV), minV, pct)));
// Denormalized values
// TODO
// Check two values "close to each other"
T d1 = 3.14;
T d0 = std::nextafter(d1, T(2));
T d2 = std::nextafter(d1, T(5));
assert(d0 < d1); // sanity checking
assert(d1 < d2); // sanity checking
// Since there's nothing in between, the midpoint has to be one or the other
T res;
res = std::midpoint(d0, d1);
assert(res == d0 || res == d1);
assert(d0 <= res);
assert(res <= d1);
res = std::midpoint(d1, d0);
assert(res == d0 || res == d1);
assert(d0 <= res);
assert(res <= d1);
res = std::midpoint(d1, d2);
assert(res == d1 || res == d2);
assert(d1 <= res);
assert(res <= d2);
res = std::midpoint(d2, d1);
assert(res == d1 || res == d2);
assert(d1 <= res);
assert(res <= d2);
}
int main (int, char**)
{
fp_test<float>();
fp_test<double>();
fp_test<long double>();
return 0;
}