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- ///////////////////////////////////////////////////////////////
- // Copyright 2012 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
- //
- // Compare results of truncated left shift to gmp, see:
- // https://svn.boost.org/trac/boost/ticket/12790
- //
- #ifdef _MSC_VER
- #define _SCL_SECURE_NO_WARNINGS
- #endif
- #include <boost/multiprecision/gmp.hpp>
- #include <boost/multiprecision/cpp_int.hpp>
- #include <boost/random/mersenne_twister.hpp>
- #include <boost/random/uniform_int.hpp>
- #include <boost/timer.hpp>
- #include "test.hpp"
- #if !defined(TEST1) && !defined(TEST2) && !defined(TEST3)
- #define TEST1
- #define TEST2
- #define TEST3
- #endif
- template <class T>
- T generate_random(unsigned bits_wanted)
- {
- static boost::random::mt19937 gen;
- typedef boost::random::mt19937::result_type random_type;
- T max_val;
- unsigned digits;
- if (std::numeric_limits<T>::is_bounded && (bits_wanted == (unsigned)std::numeric_limits<T>::digits))
- {
- max_val = (std::numeric_limits<T>::max)();
- digits = std::numeric_limits<T>::digits;
- }
- else
- {
- max_val = T(1) << bits_wanted;
- digits = bits_wanted;
- }
- unsigned bits_per_r_val = std::numeric_limits<random_type>::digits - 1;
- while ((random_type(1) << bits_per_r_val) > (gen.max)())
- --bits_per_r_val;
- unsigned terms_needed = digits / bits_per_r_val + 1;
- T val = 0;
- for (unsigned i = 0; i < terms_needed; ++i)
- {
- val *= (gen.max)();
- val += gen();
- }
- val %= max_val;
- return val;
- }
- template <class T>
- void test_value(const T& val)
- {
- boost::multiprecision::mpz_int z(val.str()), mask(1);
- mask <<= std::numeric_limits<T>::digits;
- --mask;
- for (unsigned i = 0; i <= std::numeric_limits<T>::digits + 2; ++i)
- {
- BOOST_CHECK_EQUAL((val << i).str(), boost::multiprecision::mpz_int(((z << i) & mask)).str());
- }
- }
- void test(const boost::mpl::int_<200>&) {}
- template <int N>
- void test(boost::mpl::int_<N> const&)
- {
- test(boost::mpl::int_<N + 4>());
- typedef boost::multiprecision::number<boost::multiprecision::cpp_int_backend<N, N, boost::multiprecision::unsigned_magnitude>, boost::multiprecision::et_off> mp_type;
- std::cout << "Running tests for precision: " << N << std::endl;
- mp_type mp(-1);
- test_value(mp);
- for (unsigned i = 0; i < 1000; ++i)
- test_value(generate_random<mp_type>(std::numeric_limits<mp_type>::digits));
- }
- int main()
- {
- test(boost::mpl::int_<24>());
- return boost::report_errors();
- }
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