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: Call the sqrtf function on a positive value, a positive value
10** with a decimal and on the maxium possible float value.
11**
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
34/**
35 * Helper test structure
36 */
37struct test
38{
39 float value; /* value to test the function with */
40 float expected; /* expected result */
41 float variance; /* maximum delta between the expected and actual result */
42};
43
44/**
45 * validate
46 *
47 * test validation function
48 */
49void __cdecl validate(float value, float expected, float variance)
50{
51 float result = sqrtf(value);
52
53 /*
54 * The test is valid when the difference between result
55 * and expected is less than or equal to variance
56 */
57 float delta = fabsf(result - expected);
58
59 if (delta > variance)
60 {
61 Fail("sqrtf(%g) returned %10.9g when it should have returned %10.9g",
62 value, result, expected);
63 }
64}
65
66/**
67 * validate
68 *
69 * test validation function for values returning NaN
70 */
71void __cdecl validate_isnan(float value)
72{
73 float result = sqrtf(value);
74
75 if (!_isnanf(result))
76 {
77 Fail("sqrtf(%g) returned %10.9g when it should have returned %10.9g",
78 value, result, PAL_NAN);
79 }
80}
81
82int __cdecl main(int argc, char **argv)
83{
84 struct test tests[] =
85 {
86 /* value expected variance */
87 { 0.318309886f, 0.564189584f, PAL_EPSILON }, // value: 1 / pi
88 { 0.434294482f, 0.659010229f, PAL_EPSILON }, // value: log10f(e)
89 { 0.636619772f, 0.797884561f, PAL_EPSILON }, // value: 2 / pi
90 { 0.693147181f, 0.832554611f, PAL_EPSILON }, // value: ln(2)
91 { 0.707106781f, 0.840896415f, PAL_EPSILON }, // value: 1 / sqrtf(2)
92 { 0.785398163f, 0.886226925f, PAL_EPSILON }, // value: pi / 4
93 { 1, 1, PAL_EPSILON * 10 },
94 { 1.12837917f, 1.06225193f, PAL_EPSILON * 10 }, // value: 2 / sqrtf(pi)
95 { 1.41421356f, 1.18920712f, PAL_EPSILON * 10 }, // value: sqrtf(2)
96 { 1.44269504f, 1.20112241f, PAL_EPSILON * 10 }, // value: logf2(e)
97 { 1.57079633f, 1.25331414f, PAL_EPSILON * 10 }, // value: pi / 2
98 { 2.30258509f, 1.51742713f, PAL_EPSILON * 10 }, // value: ln(10)
99 { 2.71828183f, 1.64872127f, PAL_EPSILON * 10 }, // value: e
100 { 3.14159265f, 1.77245385F, PAL_EPSILON * 10 }, // value: pi
101 };
102
103 /* PAL initialization */
104 if (PAL_Initialize(argc, argv) != 0)
105 {
106 return FAIL;
107 }
108
109 validate(-0.0f, -0.0f, PAL_EPSILON);
110 validate( 0.0f, 0.0f, PAL_EPSILON);
111
112 for (int i = 0; i < (sizeof(tests) / sizeof(struct test)); i++)
113 {
114 validate(tests[i].value, tests[i].expected, tests[i].variance);
115 validate_isnan(-tests[i].value);
116 }
117
118 validate_isnan(PAL_NAN);
119
120 PAL_Terminate();
121 return PASS;
122}
123