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- ///////////////////////////////////////////////////////////////
- // Copyright 2011 John Maddock. Distributed under the Boost
- // Software License, Version 1.0. (See accompanying file
- // LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
- //[mpfr_eg
- #include <boost/multiprecision/mpfr.hpp>
- #include <boost/math/special_functions/gamma.hpp>
- #include <iostream>
- int main()
- {
- using namespace boost::multiprecision;
- // Operations at variable precision and no numeric_limits support:
- mpfr_float a = 2;
- mpfr_float::default_precision(1000);
- std::cout << mpfr_float::default_precision() << std::endl;
- std::cout << sqrt(a) << std::endl; // print root-2
- // Operations at fixed precision and full numeric_limits support:
- mpfr_float_100 b = 2;
- std::cout << std::numeric_limits<mpfr_float_100>::digits << std::endl;
- // We can use any C++ std lib function:
- std::cout << log(b) << std::endl; // print log(2)
- // We can also use any function from Boost.Math:
- std::cout << boost::math::tgamma(b) << std::endl;
- // These even work when the argument is an expression template:
- std::cout << boost::math::tgamma(b * b) << std::endl;
- // Access the underlying data:
- mpfr_t r;
- mpfr_init(r);
- mpfr_set(r, b.backend().data(), GMP_RNDN);
- mpfr_clear(r);
- return 0;
- }
- //]
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