1//===-- Unittests for atan2 -----------------------------------------------===//
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#include "src/__support/FPUtil/FPBits.h"
10#include "src/math/atan2.h"
11#include "test/UnitTest/FPMatcher.h"
12#include "test/UnitTest/Test.h"
13#include "utils/MPFRWrapper/MPFRUtils.h"
14
15using LlvmLibcAtan2Test = LIBC_NAMESPACE::testing::FPTest<double>;
16using LIBC_NAMESPACE::testing::tlog;
17
18namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
19
20TEST_F(LlvmLibcAtan2Test, TrickyInputs) {
21 mpfr::BinaryInput<double> inputs[] = {
22 {0x1.0853408534085p-2, 0x1.e7b54166c6126p-2},
23 {FPBits::inf().get_val(), 0x0.0000000000001p-1022},
24 };
25
26 for (mpfr::BinaryInput<double> &input : inputs) {
27 double x = input.x;
28 double y = input.y;
29 mpfr::RoundingMode rm = mpfr::RoundingMode::Downward;
30 mpfr::ForceRoundingMode rr(rm);
31 ASSERT_MPFR_MATCH(mpfr::Operation::Atan2, input,
32 LIBC_NAMESPACE::atan2(x, y), 0.5, rm);
33 input.x = -input.x;
34 ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Atan2, input,
35 LIBC_NAMESPACE::atan2(-x, y), 0.5);
36 input.y = -input.y;
37 ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Atan2, input,
38 LIBC_NAMESPACE::atan2(-x, -y), 0.5);
39 input.x = -input.x;
40 ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Atan2, input,
41 LIBC_NAMESPACE::atan2(x, -y), 0.5);
42 }
43}
44
45TEST_F(LlvmLibcAtan2Test, InDoubleRange) {
46 constexpr uint64_t X_COUNT = 123;
47 constexpr uint64_t X_START = FPBits(0.25).uintval();
48 constexpr uint64_t X_STOP = FPBits(4.0).uintval();
49 constexpr uint64_t X_STEP = (X_STOP - X_START) / X_COUNT;
50
51 constexpr uint64_t Y_COUNT = 137;
52 constexpr uint64_t Y_START = FPBits(0.25).uintval();
53 constexpr uint64_t Y_STOP = FPBits(4.0).uintval();
54 constexpr uint64_t Y_STEP = (Y_STOP - Y_START) / Y_COUNT;
55
56 auto test = [&](mpfr::RoundingMode rounding_mode) {
57 mpfr::ForceRoundingMode __r(rounding_mode);
58 if (!__r.success)
59 return;
60
61 uint64_t fails = 0;
62 uint64_t finite_count = 0;
63 uint64_t total_count = 0;
64 double failed_x = 0.0, failed_y = 0.0, failed_r = 0.0;
65 double tol = 0.5;
66
67 for (uint64_t i = 0, v = X_START; i <= X_COUNT; ++i, v += X_STEP) {
68 double x = FPBits(v).get_val();
69 if (FPBits(x).is_inf_or_nan() || x < 0.0)
70 continue;
71
72 for (uint64_t j = 0, w = Y_START; j <= Y_COUNT; ++j, w += Y_STEP) {
73 double y = FPBits(w).get_val();
74 if (FPBits(y).is_inf_or_nan())
75 continue;
76
77 double result = LIBC_NAMESPACE::atan2(x, y);
78 ++total_count;
79 if (FPBits(result).is_inf_or_nan())
80 continue;
81
82 ++finite_count;
83 mpfr::BinaryInput<double> inputs{x, y};
84
85 if (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Atan2, inputs,
86 result, 0.5, rounding_mode)) {
87 ++fails;
88 while (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(
89 mpfr::Operation::Atan2, inputs, result, tol, rounding_mode)) {
90 failed_x = x;
91 failed_y = y;
92 failed_r = result;
93
94 if (tol > 1000.0)
95 break;
96
97 tol *= 2.0;
98 }
99 }
100 }
101 }
102 if (fails || (finite_count < total_count)) {
103 tlog << " Atan2 failed: " << fails << "/" << finite_count << "/"
104 << total_count << " tests.\n"
105 << " Max ULPs is at most: " << static_cast<uint64_t>(tol) << ".\n";
106 }
107 if (fails) {
108 mpfr::BinaryInput<double> inputs{failed_x, failed_y};
109 EXPECT_MPFR_MATCH(mpfr::Operation::Atan2, inputs, failed_r, 0.5,
110 rounding_mode);
111 }
112 };
113
114 tlog << " Test Rounding To Nearest...\n";
115 test(mpfr::RoundingMode::Nearest);
116
117 tlog << " Test Rounding Downward...\n";
118 test(mpfr::RoundingMode::Downward);
119
120 tlog << " Test Rounding Upward...\n";
121 test(mpfr::RoundingMode::Upward);
122
123 tlog << " Test Rounding Toward Zero...\n";
124 test(mpfr::RoundingMode::TowardZero);
125}
126

source code of libc/test/src/math/atan2_test.cpp