xref: /llvm-project/libcxx/test/support/fp_compare.h (revision 06edc1c07b447b6a2c5c70dafa24c4d6b8b3390f)
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 #ifndef SUPPORT_FP_COMPARE_H
10 #define SUPPORT_FP_COMPARE_H
11 
12 #include <algorithm> // for std::max
13 #include <cassert>
14 #include <cmath> // for std::abs
15 
16 #include "test_macros.h"
17 
18 // See https://www.boost.org/doc/libs/1_70_0/libs/test/doc/html/boost_test/testing_tools/extended_comparison/floating_point/floating_points_comparison_theory.html
19 
20 template <typename T>
21 bool fptest_close(T val, T expected, T eps) {
22   TEST_CONSTEXPR T zero = T(0);
23   assert(eps >= zero);
24 
25   // Handle the zero cases
26   if (eps == zero)
27     return val == expected;
28   if (val == zero)
29     return std::abs(expected) <= eps;
30   if (expected == zero)
31     return std::abs(val) <= eps;
32 
33   return std::abs(val - expected) < eps && std::abs(val - expected) / std::abs(val) < eps;
34 }
35 
36 template <typename T>
37 bool fptest_close_pct(T val, T expected, T percent) {
38   assert(percent >= T(0));
39   T eps = (percent / T(100)) * std::max(std::abs(val), std::abs(expected));
40   return fptest_close(val, expected, eps);
41 }
42 
43 #endif // SUPPORT_FP_COMPARE_H
44