1// Licensed to the .NET Foundation under one or more agreements.
2// The .NET Foundation licenses this file to you under the MIT license.
3// See the LICENSE file in the project root for more information.
4
5/*=====================================================================
6**
7** Source: test1.c
8**
9** Purpose: Tests that atan2f returns correct values for a subset of values.
10** Tests with positive and negative values of x and y to ensure
11** atan2f is returning results from the correct quadrant.
12**
13**===================================================================*/
14
15#include <palsuite.h>
16
17// binary32 (float) has a machine epsilon of 2^-23 (approx. 1.19e-07). However, this
18// is slightly too accurate when writing tests meant to run against libm implementations
19// for various platforms. 2^-21 (approx. 4.76e-07) seems to be as accurate as we can get.
20//
21// The tests themselves will take PAL_EPSILON and adjust it according to the expected result
22// so that the delta used for comparison will compare the most significant digits and ignore
23// any digits that are outside the double precision range (6-9 digits).
24
25// For example, a test with an expect result in the format of 0.xxxxxxxxx will use PAL_EPSILON
26// for the variance, while an expected result in the format of 0.0xxxxxxxxx will use
27// PAL_EPSILON / 10 and and expected result in the format of x.xxxxxx will use PAL_EPSILON * 10.
28#define PAL_EPSILON 4.76837158e-07
29
30#define PAL_NAN sqrtf(-1.0f)
31#define PAL_POSINF -logf(0.0f)
32#define PAL_NEGINF logf(0.0f)
33
34struct test
35{
36 float y; /* second component of the value to test the function with */
37 float x; /* first component of the value to test the function with */
38 float expected; /* expected result */
39 float variance; /* maximum delta between the expected and actual result */
40};
41
42/**
43 * validate
44 *
45 * test validation function
46 */
47void __cdecl validate(float y, float x, float expected, float variance)
48{
49 float result = atan2f(y, x);
50
51 /*
52 * The test is valid when the difference between result
53 * and expected is less than or equal to variance
54 */
55 float delta = fabsf(result - expected);
56
57 if (delta > variance)
58 {
59 Fail("atan2f(%g, %g) returned %10.9g when it should have returned %10.9g",
60 y, x, result, expected);
61 }
62}
63
64/**
65 * validate
66 *
67 * test validation function for values returning NaN
68 */
69void __cdecl validate_isnan(float y, float x)
70{
71 float result = atan2f(y, x);
72
73 if (!_isnanf(result))
74 {
75 Fail("atan2f(%g, %g) returned %10.9g when it should have returned %10.9g",
76 y, x, result, PAL_NAN);
77 }
78}
79
80/**
81 * main
82 *
83 * executable entry point
84 */
85int __cdecl main(int argc, char **argv)
86{
87 struct test tests[] =
88 {
89 /* y x expected variance */
90 { 0, PAL_POSINF, 0, PAL_EPSILON },
91 { 0, 0, 0, PAL_EPSILON },
92 { 0.312961796f, 0.949765715f, 0.318309886f, PAL_EPSILON }, // expected: 1 / pi
93 { 0.420770483f, 0.907167129f, 0.434294482f, PAL_EPSILON }, // expected: logf10f(e)
94 { 0.594480769f, 0.804109828f, 0.636619772f, PAL_EPSILON }, // expected: 2 / pi
95 { 0.638961276f, 0.769238901f, 0.693147181f, PAL_EPSILON }, // expected: ln(2)
96 { 0.649636939f, 0.760244597f, 0.707106781f, PAL_EPSILON }, // expected: 1 / sqrtf(2)
97 { 0.707106781f, 0.707106781f, 0.785398163f, PAL_EPSILON }, // expected: pi / 4, value: 1 / sqrtf(2)
98 { 1, 1, 0.785398163f, PAL_EPSILON }, // expected: pi / 4
99 { PAL_POSINF, PAL_POSINF, 0.785398163f, PAL_EPSILON }, // expected: pi / 4
100 { 0.841470985f, 0.540302306f, 1, PAL_EPSILON * 10 },
101 { 0.903719457f, 0.428125148f, 1.12837917f, PAL_EPSILON * 10 }, // expected: 2 / sqrtf(pi)
102 { 0.987765946f, 0.155943695f, 1.41421356f, PAL_EPSILON * 10 }, // expected: sqrtf(2)
103 { 0.991806244f, 0.127751218f, 1.44269504f, PAL_EPSILON * 10 }, // expected: logf2(e)
104 { 1, 0, 1.57079633f, PAL_EPSILON * 10 }, // expected: pi / 2
105 { PAL_POSINF, 0, 1.57079633f, PAL_EPSILON * 10 }, // expected: pi / 2
106 { PAL_POSINF, 1, 1.57079633f, PAL_EPSILON * 10 }, // expected: pi / 2
107 { 0.743980337f, -0.668201510f, 2.30258509f, PAL_EPSILON * 10 }, // expected: ln(10)
108 { 0.410781291f, -0.911733915f, 2.71828183f, PAL_EPSILON * 10 }, // expected: e
109 { 0, -1, 3.14159265f, PAL_EPSILON * 10 }, // expected: pi
110 { 1, PAL_POSINF, 0, PAL_EPSILON },
111 };
112
113 if (PAL_Initialize(argc, argv) != 0)
114 {
115 return FAIL;
116 }
117
118 for (int i = 0; i < (sizeof(tests) / sizeof(struct test)); i++)
119 {
120 const float pi = 3.14159265f;
121
122 validate( tests[i].y, tests[i].x, tests[i].expected, tests[i].variance);
123 validate(-tests[i].y, tests[i].x, -tests[i].expected, tests[i].variance);
124 validate( tests[i].y, -tests[i].x, pi - tests[i].expected, tests[i].variance);
125 validate(-tests[i].y, -tests[i].x, tests[i].expected - pi, tests[i].variance);
126 }
127
128 validate_isnan(PAL_NEGINF, PAL_NAN);
129 validate_isnan(PAL_NAN, PAL_NEGINF);
130 validate_isnan(PAL_NAN, PAL_POSINF);
131 validate_isnan(PAL_POSINF, PAL_NAN);
132
133 validate_isnan(PAL_NAN, -1);
134 validate_isnan(PAL_NAN, -0.0f);
135 validate_isnan(PAL_NAN, 0);
136 validate_isnan(PAL_NAN, 1);
137
138 validate_isnan(-1, PAL_NAN);
139 validate_isnan(-0.0f, PAL_NAN);
140 validate_isnan( 0, PAL_NAN);
141 validate_isnan( 1, PAL_NAN);
142
143 validate_isnan(PAL_NAN, PAL_NAN);
144
145 PAL_Terminate();
146 return PASS;
147}
148