41 lines
1.5 KiB
C++
41 lines
1.5 KiB
C++
///////////////////////////////////////////////////////////////////////////////
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// Copyright 2016 John Maddock. Distributed under the Boost
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// 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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#include <boost/multiprecision/cpp_bin_float.hpp>
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int main()
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{
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typedef boost::multiprecision::number<boost::multiprecision::backends::cpp_bin_float<256> > ext_float_t;
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typedef boost::multiprecision::number<boost::multiprecision::backends::cpp_bin_float<2046> > long_ext_float_t;
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ext_float_t x = 5e15;
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x += 0.5;
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ext_float_t x1 = x + 255.0 / (1 << 20); // + 2^-12 - eps
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ext_float_t x2 = x + 257.0 / (1 << 20); // + 2^-12 + eps
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double d1 = x1.convert_to<double>();
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double d2 = x2.convert_to<double>();
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std::cout << std::setprecision(18) << d1 << std::endl;
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std::cout << std::setprecision(18) << d2 << std::endl;
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x = 1e7 + 0.5;
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x1 = x + ldexp(255.0, -38); // + 2^-30 - eps
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x2 = x + ldexp(257.0, -38); // + 2^-30 + eps
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float f1 = x1.convert_to<float>();
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float f2 = x2.convert_to<float>();
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std::cout << std::setprecision(9) << f1 << std::endl;
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std::cout << std::setprecision(9) << f2 << std::endl;
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long_ext_float_t lf(1);
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lf += std::numeric_limits<long_ext_float_t>::epsilon();
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lf += std::numeric_limits<float>::epsilon() / 2;
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BOOST_ASSERT(lf != 1);
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float f3 = lf.convert_to<float>();
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std::cout << std::setprecision(9) << f3 << std::endl;
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return (d1 == d2) && (f1 == f2) && (f3 != 1) ? 0 : 1;
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}
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