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: Test to ensure that fabsf return the correct values
10**
11** Dependencies: PAL_Initialize
12** PAL_Terminate
13** Fail
14**
15**===========================================================================*/
16
17#include <palsuite.h>
18
19// binary32 (float) has a machine epsilon of 2^-23 (approx. 1.19e-07). However, this
20// is slightly too accurate when writing tests meant to run against libm implementations
21// for various platforms. 2^-21 (approx. 4.76e-07) seems to be as accurate as we can get.
22//
23// The tests themselves will take PAL_EPSILON and adjust it according to the expected result
24// so that the delta used for comparison will compare the most significant digits and ignore
25// any digits that are outside the double precision range (6-9 digits).
26
27// For example, a test with an expect result in the format of 0.xxxxxxxxx will use PAL_EPSILON
28// for the variance, while an expected result in the format of 0.0xxxxxxxxx will use
29// PAL_EPSILON / 10 and and expected result in the format of x.xxxxxx will use PAL_EPSILON * 10.
30#define PAL_EPSILON 4.76837158e-07
31
32
33#define PAL_NAN sqrt(-1.0)
34#define PAL_POSINF -log(0.0)
35#define PAL_NEGINF log(0.0)
36
37/**
38 * Helper test structure
39 */
40struct test
41{
42 float value; /* value to test the function with */
43 float expected; /* expected result */
44 float variance; /* maximum delta between the expected and actual result */
45};
46
47/**
48 * validate
49 *
50 * test validation function
51 */
52void __cdecl validate(float value, float expected, float variance)
53{
54 float result = fabsf(value);
55
56 /*
57 * The test is valid when the difference between result
58 * and expected is less than or equal to variance
59 */
60 float delta = fabsf(result - expected);
61
62 if (delta > variance)
63 {
64 Fail("fabsf(%g) returned %10.9g when it should have returned %10.9g",
65 value, result, expected);
66 }
67}
68
69/**
70 * validate
71 *
72 * test validation function for values returning NaN
73 */
74void __cdecl validate_isnan(float value)
75{
76 float result = fabsf(value);
77
78 if (!_isnan(result))
79 {
80 Fail("fabsf(%g) returned %10.9g when it should have returned %10.9g",
81 value, result, PAL_NAN);
82 }
83}
84
85/**
86 * main
87 *
88 * executable entry point
89 */
90INT __cdecl main(INT argc, CHAR **argv)
91{
92 struct test tests[] =
93 {
94 /* value expected variance */
95 { PAL_NEGINF, PAL_POSINF, 0 },
96 { -3.14159265f, 3.14159265f, PAL_EPSILON * 10 }, // value: -(pi) expected: pi
97 { -2.71828183f, 2.71828183f, PAL_EPSILON * 10 }, // value: -(e) expected: e
98 { -2.30258509f, 2.30258509f, PAL_EPSILON * 10 }, // value: -(ln(10)) expected: ln(10)
99 { -1.57079633f, 1.57079633f, PAL_EPSILON * 10 }, // value: -(pi / 2) expected: pi / 2
100 { -1.44269504f, 1.44269504f, PAL_EPSILON * 10 }, // value: -(log2(e)) expected: log2(e)
101 { -1.41421356f, 1.41421356f, PAL_EPSILON * 10 }, // value: -(sqrt(2)) expected: sqrt(2)
102 { -1.12837917f, 1.12837917f, PAL_EPSILON * 10 }, // value: -(2 / sqrt(pi)) expected: 2 / sqrt(pi)
103 { -1, 1, PAL_EPSILON * 10 },
104 { -0.785398163f, 0.785398163f, PAL_EPSILON }, // value: -(pi / 4) expected: pi / 4
105 { -0.707106781f, 0.707106781f, PAL_EPSILON }, // value: -(1 / sqrt(2)) expected: 1 / sqrt(2)
106 { -0.693147181f, 0.693147181f, PAL_EPSILON }, // value: -(ln(2)) expected: ln(2)
107 { -0.636619772f, 0.636619772f, PAL_EPSILON }, // value: -(2 / pi) expected: 2 / pi
108 { -0.434294482f, 0.434294482f, PAL_EPSILON }, // value: -(log10(e)) expected: log10(e)
109 { -0.318309886f, 0.318309886f, PAL_EPSILON }, // value: -(1 / pi) expected: 1 / pi
110 { -0.0f, 0, PAL_EPSILON },
111 };
112
113
114 // PAL initialization
115 if (PAL_Initialize(argc, argv) != 0)
116 {
117 return FAIL;
118 }
119
120 for (int i = 0; i < (sizeof(tests) / sizeof(struct test)); i++)
121 {
122 validate( tests[i].value, tests[i].expected, tests[i].variance);
123 validate(-tests[i].value, tests[i].expected, tests[i].variance);
124 }
125
126 validate_isnan(PAL_NAN);
127
128 PAL_Terminate();
129 return PASS;
130}
131