1 #define BOOST_TEST_MAIN// Copyright John Maddock 2008
2 // (C) Copyright Paul A. Bristow 2011 (added tests for changesign)
3 // Use, modification and distribution are subject to the
4 // Boost Software License, Version 1.0.
5 // (See accompanying file LICENSE_1_0.txt
6 // or copy at http://www.boost.org/LICENSE_1_0.txt)
7
8 #include <boost/math/concepts/real_concept.hpp> // for real_concept
9 #include <boost/math/special_functions/sign.hpp>
10
11 #define BOOST_TEST_MAIN
12 #include <boost/test/unit_test.hpp> // Boost.Test
13 #include <boost/test/results_collector.hpp>
14 #include <boost/test/unit_test.hpp>
15 #include <boost/test/tools/floating_point_comparison.hpp>
16
17 #include <iostream>
18 using std::cout;
19 using std::endl;
20 using std::setprecision;
21
22 template <class RealType>
test_spots(RealType,const char *)23 void test_spots(RealType /*T*/, const char* /*type_name*/)
24 {
25 // Basic sanity checks.
26 RealType a = 0;
27 RealType b = 1;
28 RealType c = -1;
29 BOOST_CHECK_EQUAL((boost::math::signbit)(a), 0);
30 BOOST_CHECK_EQUAL((boost::math::sign)(a), 0);
31 BOOST_CHECK_EQUAL((boost::math::changesign)(b), RealType(-1));
32 BOOST_CHECK_EQUAL((boost::math::changesign)(c), RealType(+1));
33 BOOST_CHECK_EQUAL((boost::math::changesign)(a), RealType(0));
34
35 // Compare to formula for changsign(x) = copysign(x, signbit(x) ? 1.0 : -1.0)
36 BOOST_CHECK_EQUAL((boost::math::changesign)(b),
37 (boost::math::copysign)(b, (boost::math::signbit)(b) ? RealType(1.) : RealType(-1.) ));
38
39
40 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(1));
41 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(1));
42 a = 1;
43 BOOST_CHECK_EQUAL((boost::math::signbit)(a), 0);
44 BOOST_CHECK_EQUAL((boost::math::sign)(a), 1);
45 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(1));
46 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(1));
47 a = -1;
48 BOOST_CHECK((boost::math::signbit)(a) != 0);
49 BOOST_CHECK_EQUAL((boost::math::sign)(a), -1);
50 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(-1));
51 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(-1));
52 a = boost::math::tools::max_value<RealType>();
53 BOOST_CHECK_EQUAL((boost::math::signbit)(a), 0);
54 BOOST_CHECK_EQUAL((boost::math::sign)(a), 1);
55 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(1));
56 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(1));
57 a = -boost::math::tools::max_value<RealType>();
58 BOOST_CHECK((boost::math::signbit)(a) != 0);
59 BOOST_CHECK_EQUAL((boost::math::sign)(a), -1);
60 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(-1));
61 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(-1));
62
63 if(std::numeric_limits<RealType>::has_infinity)
64 {
65 a = std::numeric_limits<RealType>::infinity();
66 BOOST_CHECK_EQUAL((boost::math::signbit)(a), 0);
67 BOOST_CHECK_EQUAL((boost::math::sign)(a), 1);
68 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(1));
69 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(1));
70 BOOST_CHECK_EQUAL((boost::math::changesign)(a), -a);
71
72 a = -std::numeric_limits<RealType>::infinity();
73 BOOST_CHECK((boost::math::signbit)(a) != 0);
74 BOOST_CHECK_EQUAL((boost::math::sign)(a), -1);
75 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(-1));
76 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(-1));
77 BOOST_CHECK_EQUAL((boost::math::changesign)(a), -a);
78 }
79 #if !defined(__SUNPRO_CC) && !defined(BOOST_INTEL)
80 if(std::numeric_limits<RealType>::has_quiet_NaN)
81 {
82 a = std::numeric_limits<RealType>::quiet_NaN();
83 BOOST_CHECK_EQUAL((boost::math::signbit)(a), 0);
84 BOOST_CHECK_EQUAL((boost::math::sign)(a), 1);
85 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(1));
86 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(1));
87 // BOOST_CHECK_EQUAL((boost::math::changesign)(a), -a); // NaN comparison fails always!
88 BOOST_CHECK((boost::math::signbit)((boost::math::changesign)(a)) != 0);
89
90 a = -std::numeric_limits<RealType>::quiet_NaN();
91 BOOST_CHECK((boost::math::signbit)(a) != 0);
92 BOOST_CHECK_EQUAL((boost::math::sign)(a), -1);
93 BOOST_CHECK_EQUAL((boost::math::copysign)(b, a), RealType(-1));
94 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(-1));
95 //BOOST_CHECK_EQUAL((boost::math::changesign)(a), -a); // NaN comparison fails always!
96 BOOST_CHECK_EQUAL((boost::math::signbit)((boost::math::changesign)(a)), 0);
97
98 }
99 #endif
100 //
101 // Try some extreme values:
102 //
103 a = boost::math::tools::min_value<RealType>();
104 b = -a;
105 c = -1;
106 BOOST_CHECK((boost::math::signbit)(a) == 0);
107 BOOST_CHECK_EQUAL((boost::math::sign)(a), 1);
108 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(1));
109 BOOST_CHECK((boost::math::signbit)(b) != 0);
110 BOOST_CHECK_EQUAL((boost::math::sign)(b), -1);
111 c = 1;
112 BOOST_CHECK_EQUAL((boost::math::copysign)(c, b), RealType(-1));
113 //
114 // try denormalised values:
115 //
116 a /= 4;
117 if(a != 0)
118 {
119 b = -a;
120 c = -1;
121 BOOST_CHECK((boost::math::signbit)(a) == 0);
122 BOOST_CHECK_EQUAL((boost::math::sign)(a), 1);
123 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(1));
124 BOOST_CHECK((boost::math::signbit)(b) != 0);
125 BOOST_CHECK_EQUAL((boost::math::sign)(b), -1);
126 c = 1;
127 BOOST_CHECK_EQUAL((boost::math::copysign)(c, b), RealType(-1));
128 }
129 a = boost::math::tools::max_value<RealType>() / 2;
130 b = -a;
131 c = -1;
132 BOOST_CHECK((boost::math::signbit)(a) == 0);
133 BOOST_CHECK_EQUAL((boost::math::sign)(a), 1);
134 BOOST_CHECK_EQUAL((boost::math::copysign)(c, a), RealType(1));
135 BOOST_CHECK((boost::math::signbit)(b) != 0);
136 BOOST_CHECK_EQUAL((boost::math::sign)(b), -1);
137 c = 1;
138 BOOST_CHECK_EQUAL((boost::math::copysign)(c, b), RealType(-1));
139 }
140
141
BOOST_AUTO_TEST_CASE(test_main)142 BOOST_AUTO_TEST_CASE( test_main )
143 {
144 // Basic sanity-check spot values.
145 // (Parameter value, arbitrarily zero, only communicates the floating point type).
146 test_spots(0.0F, "float"); // Test float. OK at decdigits = 0 tolerance = 0.0001 %
147 test_spots(0.0, "double"); // Test double. OK at decdigits 7, tolerance = 1e07 %
148 // long double support for the sign functions is considered "core" so we always test it
149 // even when long double support is turned off via BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
150 test_spots(0.0L, "long double"); // Test long double.
151 #ifndef BOOST_MATH_NO_REAL_CONCEPT_TESTS
152 test_spots(boost::math::concepts::real_concept(0), "real_concept"); // Test real_concept.
153 #endif
154
155
156 } // BOOST_AUTO_TEST_CASE( test_main )
157
158