120 lines
4.2 KiB
C++
120 lines
4.2 KiB
C++
// Use, modification and distribution are subject to the
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// Boost Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// Copyright Paul A. Bristow 2013
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// Copyright Christopher Kormanyos 2013.
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// Copyright John Maddock 2013.
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#ifdef _MSC_VER
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# pragma warning (disable : 4512)
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# pragma warning (disable : 4996)
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#endif
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#define BOOST_TEST_MAIN
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#define BOOST_LIB_DIAGNOSTIC "on"// Show library file details.
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#include <boost/test/unit_test.hpp>
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#include <boost/test/tools/floating_point_comparison.hpp> // Extra test tool for FP comparison.
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#include <iostream>
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#include <limits>
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//[expression_template_1
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#include <boost/multiprecision/cpp_dec_float.hpp>
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/*`To define a 50 decimal digit type using `cpp_dec_float`,
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you must pass two template parameters to `boost::multiprecision::number`.
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It may be more legible to use a two-staged type definition such as this:
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``
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typedef boost::multiprecision::cpp_dec_float<50> mp_backend;
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typedef boost::multiprecision::number<mp_backend, boost::multiprecision::et_off> cpp_dec_float_50_noet;
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``
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Here, we first define `mp_backend` as `cpp_dec_float` with 50 digits.
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The second step passes this backend to `boost::multiprecision::number`
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with `boost::multiprecision::et_off`, an enumerated type.
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typedef boost::multiprecision::number<boost::multiprecision::cpp_dec_float<50>, boost::multiprecision::et_off>
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cpp_dec_float_50_noet;
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You can reduce typing with a `using` directive `using namespace boost::multiprecision;`
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if desired, as shown below.
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*/
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using namespace boost::multiprecision;
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/*`Now `cpp_dec_float_50_noet` or `cpp_dec_float_50_et`
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can be used as a direct replacement for built-in types like `double` etc.
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*/
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BOOST_AUTO_TEST_CASE(cpp_float_test_check_close_noet)
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{ // No expression templates/
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typedef number<cpp_dec_float<50>, et_off> cpp_dec_float_50_noet;
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std::cout.precision(std::numeric_limits<cpp_dec_float_50_noet>::digits10); // All significant digits.
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std::cout << std::showpoint << std::endl; // Show trailing zeros.
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cpp_dec_float_50_noet a ("1.0");
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cpp_dec_float_50_noet b ("1.0");
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b += std::numeric_limits<cpp_dec_float_50_noet>::epsilon(); // Increment least significant decimal digit.
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cpp_dec_float_50_noet eps = std::numeric_limits<cpp_dec_float_50_noet>::epsilon();
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std::cout <<"a = " << a << ",\nb = " << b << ",\neps = " << eps << std::endl;
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BOOST_CHECK_CLOSE(a, b, eps * 100); // Expected to pass (because tolerance is as percent).
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BOOST_CHECK_CLOSE_FRACTION(a, b, eps); // Expected to pass (because tolerance is as fraction).
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} // BOOST_AUTO_TEST_CASE(cpp_float_test_check_close)
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BOOST_AUTO_TEST_CASE(cpp_float_test_check_close_et)
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{ // Using expression templates.
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typedef number<cpp_dec_float<50>, et_on> cpp_dec_float_50_et;
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std::cout.precision(std::numeric_limits<cpp_dec_float_50_et>::digits10); // All significant digits.
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std::cout << std::showpoint << std::endl; // Show trailing zeros.
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cpp_dec_float_50_et a("1.0");
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cpp_dec_float_50_et b("1.0");
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b += std::numeric_limits<cpp_dec_float_50_et>::epsilon(); // Increment least significant decimal digit.
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cpp_dec_float_50_et eps = std::numeric_limits<cpp_dec_float_50_et>::epsilon();
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std::cout << "a = " << a << ",\nb = " << b << ",\neps = " << eps << std::endl;
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BOOST_CHECK_CLOSE(a, b, eps * 100); // Expected to pass (because tolerance is as percent).
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BOOST_CHECK_CLOSE_FRACTION(a, b, eps); // Expected to pass (because tolerance is as fraction).
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/*`Using `cpp_dec_float_50` with the default expression template use switched on,
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the compiler error message for `BOOST_CHECK_CLOSE_FRACTION(a, b, eps); would be:
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*/
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// failure floating_point_comparison.hpp(59): error C2440: 'static_cast' :
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// cannot convert from 'int' to 'boost::multiprecision::detail::expression<tag,Arg1,Arg2,Arg3,Arg4>'
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//] [/expression_template_1]
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} // BOOST_AUTO_TEST_CASE(cpp_float_test_check_close)
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/*
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Output:
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Description: Autorun "J:\Cpp\big_number\Debug\test_cpp_float_close_fraction.exe"
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Running 1 test case...
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a = 1.0000000000000000000000000000000000000000000000000,
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b = 1.0000000000000000000000000000000000000000000000001,
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eps = 1.0000000000000000000000000000000000000000000000000e-49
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*** No errors detected
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*/
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