1 // Use, modification and distribution are subject to the
2 // Boost Software License, Version 1.0. (See accompanying file
3 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
4
5 // Copyright Paul A. Bristow 2013
6 // Copyright Christopher Kormanyos 2013.
7 // Copyright John Maddock 2013.
8
9 #ifdef _MSC_VER
10 # pragma warning (disable : 4512)
11 # pragma warning (disable : 4996)
12 #endif
13
14 #define BOOST_TEST_MAIN
15 #define BOOST_LIB_DIAGNOSTIC "on"// Show library file details.
16
17 #include <boost/test/unit_test.hpp>
18 #include <boost/test/tools/floating_point_comparison.hpp> // Extra test tool for FP comparison.
19
20 #include <iostream>
21 #include <limits>
22
23 //[expression_template_1
24
25 #include <boost/multiprecision/cpp_dec_float.hpp>
26
27 /*`To define a 50 decimal digit type using `cpp_dec_float`,
28 you must pass two template parameters to `boost::multiprecision::number`.
29
30 It may be more legible to use a two-staged type definition such as this:
31
32 ``
33 typedef boost::multiprecision::cpp_dec_float<50> mp_backend;
34 typedef boost::multiprecision::number<mp_backend, boost::multiprecision::et_off> cpp_dec_float_50_noet;
35 ``
36
37 Here, we first define `mp_backend` as `cpp_dec_float` with 50 digits.
38 The second step passes this backend to `boost::multiprecision::number`
39 with `boost::multiprecision::et_off`, an enumerated type.
40
41 typedef boost::multiprecision::number<boost::multiprecision::cpp_dec_float<50>, boost::multiprecision::et_off>
42 cpp_dec_float_50_noet;
43
44 You can reduce typing with a `using` directive `using namespace boost::multiprecision;`
45 if desired, as shown below.
46 */
47
48 using namespace boost::multiprecision;
49
50
51 /*`Now `cpp_dec_float_50_noet` or `cpp_dec_float_50_et`
52 can be used as a direct replacement for built-in types like `double` etc.
53 */
54
BOOST_AUTO_TEST_CASE(cpp_float_test_check_close_noet)55 BOOST_AUTO_TEST_CASE(cpp_float_test_check_close_noet)
56 { // No expression templates/
57 typedef number<cpp_dec_float<50>, et_off> cpp_dec_float_50_noet;
58
59 std::cout.precision(std::numeric_limits<cpp_dec_float_50_noet>::digits10); // All significant digits.
60 std::cout << std::showpoint << std::endl; // Show trailing zeros.
61
62 cpp_dec_float_50_noet a ("1.0");
63 cpp_dec_float_50_noet b ("1.0");
64 b += std::numeric_limits<cpp_dec_float_50_noet>::epsilon(); // Increment least significant decimal digit.
65
66 cpp_dec_float_50_noet eps = std::numeric_limits<cpp_dec_float_50_noet>::epsilon();
67
68 std::cout <<"a = " << a << ",\nb = " << b << ",\neps = " << eps << std::endl;
69
70 BOOST_CHECK_CLOSE(a, b, eps * 100); // Expected to pass (because tolerance is as percent).
71 BOOST_CHECK_CLOSE_FRACTION(a, b, eps); // Expected to pass (because tolerance is as fraction).
72
73
74
75 } // BOOST_AUTO_TEST_CASE(cpp_float_test_check_close)
76
BOOST_AUTO_TEST_CASE(cpp_float_test_check_close_et)77 BOOST_AUTO_TEST_CASE(cpp_float_test_check_close_et)
78 { // Using expression templates.
79 typedef number<cpp_dec_float<50>, et_on> cpp_dec_float_50_et;
80
81 std::cout.precision(std::numeric_limits<cpp_dec_float_50_et>::digits10); // All significant digits.
82 std::cout << std::showpoint << std::endl; // Show trailing zeros.
83
84 cpp_dec_float_50_et a("1.0");
85 cpp_dec_float_50_et b("1.0");
86 b += std::numeric_limits<cpp_dec_float_50_et>::epsilon(); // Increment least significant decimal digit.
87
88 cpp_dec_float_50_et eps = std::numeric_limits<cpp_dec_float_50_et>::epsilon();
89
90 std::cout << "a = " << a << ",\nb = " << b << ",\neps = " << eps << std::endl;
91
92 BOOST_CHECK_CLOSE(a, b, eps * 100); // Expected to pass (because tolerance is as percent).
93 BOOST_CHECK_CLOSE_FRACTION(a, b, eps); // Expected to pass (because tolerance is as fraction).
94
95 /*`Using `cpp_dec_float_50` with the default expression template use switched on,
96 the compiler error message for `BOOST_CHECK_CLOSE_FRACTION(a, b, eps); would be:
97 */
98 // failure floating_point_comparison.hpp(59): error C2440: 'static_cast' :
99 // cannot convert from 'int' to 'boost::multiprecision::detail::expression<tag,Arg1,Arg2,Arg3,Arg4>'
100 //] [/expression_template_1]
101
102 } // BOOST_AUTO_TEST_CASE(cpp_float_test_check_close)
103
104 /*
105
106 Output:
107
108 Description: Autorun "J:\Cpp\big_number\Debug\test_cpp_float_close_fraction.exe"
109 Running 1 test case...
110
111 a = 1.0000000000000000000000000000000000000000000000000,
112 b = 1.0000000000000000000000000000000000000000000000001,
113 eps = 1.0000000000000000000000000000000000000000000000000e-49
114
115 *** No errors detected
116
117
118 */
119
120