multiprecision/test/test_rat_float_interconv.cpp

295 lines
9.2 KiB
C++

// Copyright John Maddock 2013.
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt
// or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifdef _MSC_VER
#define _SCL_SECURE_NO_WARNINGS
#endif
#if defined(TEST1) || defined(TEST2) || defined(TEST3) || defined(TEST4)
#include <boost/multiprecision/cpp_bin_float.hpp>
#include <boost/multiprecision/cpp_int.hpp>
#else
#include <boost/multiprecision/mpfr.hpp>
#endif
#include <boost/math/special_functions/next.hpp>
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int.hpp>
#include <boost/chrono.hpp>
#include "test.hpp"
#include <boost/array.hpp>
#include <iostream>
#include <iomanip>
#ifdef BOOST_MSVC
#pragma warning(disable : 4127)
#endif
template <class Clock>
struct stopwatch
{
typedef typename Clock::duration duration;
stopwatch()
{
m_start = Clock::now();
}
duration elapsed()
{
return Clock::now() - m_start;
}
void reset()
{
m_start = Clock::now();
}
private:
typename Clock::time_point m_start;
};
template <class T>
struct exponent_type
{
typedef int type;
};
template <class T, boost::multiprecision::expression_template_option ET>
struct exponent_type<boost::multiprecision::number<T, ET> >
{
typedef typename T::exponent_type type;
};
template <class T>
T generate_random_float()
{
BOOST_MATH_STD_USING
typedef typename exponent_type<T>::type e_type;
static boost::random::mt19937 gen;
T val = gen();
T prev_val = -1;
while (val != prev_val)
{
val *= (gen.max)();
prev_val = val;
val += gen();
}
e_type e;
val = frexp(val, &e);
static const int max_exponent_value = (std::min)(static_cast<int>(std::numeric_limits<T>::max_exponent - std::numeric_limits<T>::digits - 20), 2000);
static boost::random::uniform_int_distribution<e_type> ui(0, max_exponent_value);
return ldexp(val, ui(gen));
}
template <class Float, class Rat>
void do_round_trip(const Float& val)
{
#ifndef BOOST_MP_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
BOOST_MATH_STD_USING
Rat rat(val);
Float new_f(rat);
BOOST_CHECK_EQUAL(val, new_f);
//
// Try adding or subtracting an insignificant amount
// (0.25ulp) from rat and check that it rounds to the same value:
//
typename exponent_type<Float>::type e;
Float t = frexp(val, &e);
(void)t; // warning suppression
e -= std::numeric_limits<Float>::digits + 2;
BOOST_ASSERT(val == (val + ldexp(Float(1), e)));
Rat delta, rounded;
typedef typename boost::multiprecision::component_type<Rat>::type i_type;
i_type i(1);
i <<= (e < 0 ? -e : e);
if (e > 0)
delta.assign(i);
else
delta = Rat(i_type(1), i);
rounded = rat + delta;
new_f = static_cast<Float>(rounded);
BOOST_CHECK_EQUAL(val, new_f);
rounded = rat - delta;
new_f = static_cast<Float>(rounded);
BOOST_CHECK_EQUAL(val, new_f);
delta /= 2;
rounded = rat + delta;
new_f = static_cast<Float>(rounded);
BOOST_CHECK_EQUAL(val, new_f);
rounded = rat - delta;
new_f = static_cast<Float>(rounded);
BOOST_CHECK_EQUAL(val, new_f);
delta /= 2;
rounded = rat + delta;
new_f = static_cast<Float>(rounded);
BOOST_CHECK_EQUAL(val, new_f);
rounded = rat - delta;
new_f = static_cast<Float>(rounded);
BOOST_CHECK_EQUAL(val, new_f);
#endif
}
template <class Float, class Rat>
void test_round_trip()
{
#ifndef BOOST_MP_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
std::cout << "Testing types " << typeid(Float).name() << " <<==>> " << typeid(Rat).name() << std::endl;
std::cout << "digits = " << std::numeric_limits<Float>::digits << std::endl;
std::cout << "digits10 = " << std::numeric_limits<Float>::digits10 << std::endl;
#ifndef BOOST_NO_CXX11_NUMERIC_LIMITS
std::cout << "max_digits10 = " << std::numeric_limits<Float>::max_digits10 << std::endl;
#endif
stopwatch<boost::chrono::high_resolution_clock> w;
int count = 0;
#ifndef CI_SUPPRESS_KNOWN_ISSUES
while (boost::chrono::duration_cast<boost::chrono::duration<double> >(w.elapsed()).count() < 200)
#else
while (boost::chrono::duration_cast<boost::chrono::duration<double> >(w.elapsed()).count() < 50)
#endif
{
Float val = generate_random_float<Float>();
do_round_trip<Float, Rat>(val);
do_round_trip<Float, Rat>(Float(-val));
do_round_trip<Float, Rat>(Float(1 / val));
do_round_trip<Float, Rat>(Float(-1 / val));
count += 4;
if (boost::detail::test_errors() > 100)
break;
}
std::cout << "Execution time = " << boost::chrono::duration_cast<boost::chrono::duration<double> >(w.elapsed()).count() << "s" << std::endl;
std::cout << "Total values tested: " << count << std::endl;
#endif
}
template <class Int>
Int generate_random_int()
{
static boost::random::mt19937 gen;
static boost::random::uniform_int_distribution<boost::random::mt19937::result_type> d(1, 20);
int lim;
Int cppi(0);
lim = d(gen);
for (int i = 0; i < lim; ++i)
{
cppi *= (gen.max)();
cppi += gen();
}
return cppi;
}
template <class Float, class Rat>
void test_random_rationals()
{
#ifndef BOOST_MP_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
std::cout << "Testing types " << typeid(Float).name() << " <<==>> " << typeid(Rat).name() << std::endl;
std::cout << "digits = " << std::numeric_limits<Float>::digits << std::endl;
std::cout << "digits10 = " << std::numeric_limits<Float>::digits10 << std::endl;
#ifndef BOOST_NO_CXX11_NUMERIC_LIMITS
std::cout << "max_digits10 = " << std::numeric_limits<Float>::max_digits10 << std::endl;
#endif
typedef typename boost::multiprecision::component_type<Rat>::type i_type;
stopwatch<boost::chrono::high_resolution_clock> w;
int count = 0;
#ifndef CI_SUPPRESS_KNOWN_ISSUES
while (boost::chrono::duration_cast<boost::chrono::duration<double> >(w.elapsed()).count() < 200)
#else
while (boost::chrono::duration_cast<boost::chrono::duration<double> >(w.elapsed()).count() < 50)
#endif
{
Rat rat(generate_random_int<i_type>(), generate_random_int<i_type>());
Float f(rat);
Rat new_rat(f); // rounded value
int c = new_rat.compare(rat);
if (c < 0)
{
// If f was rounded down, next float up must be above the original value:
f = boost::math::float_next(f);
new_rat.assign(f);
BOOST_CHECK(new_rat >= rat);
}
else if (c > 0)
{
// If f was rounded up, next float down must be below the original value:
f = boost::math::float_prior(f);
new_rat.assign(f);
BOOST_CHECK(new_rat <= rat);
}
else
{
// Values were equal... nothing to test.
}
if (boost::detail::test_errors() > 100)
break;
}
std::cout << "Execution time = " << boost::chrono::duration_cast<boost::chrono::duration<double> >(w.elapsed()).count() << "s" << std::endl;
std::cout << "Total values tested: " << count << std::endl;
#endif
}
#if defined(TEST2)
void double_spot_tests()
{
boost::multiprecision::cpp_rational rat = 1;
boost::multiprecision::cpp_rational twiddle(boost::multiprecision::cpp_int(1), boost::multiprecision::cpp_int(boost::multiprecision::cpp_int(1) << 54));
rat += boost::multiprecision::cpp_rational(boost::multiprecision::cpp_int(1), boost::multiprecision::cpp_int(boost::multiprecision::cpp_int(1) << 50));
double d = rat.convert_to<double>();
rat += twiddle;
BOOST_CHECK_EQUAL(d, rat.convert_to<double>());
rat += twiddle;
// tie: round to even rounds down
BOOST_CHECK_EQUAL(d, rat.convert_to<double>());
rat += twiddle;
BOOST_CHECK_NE(d, rat.convert_to<double>());
rat -= twiddle;
BOOST_CHECK_EQUAL(d, rat.convert_to<double>());
rat += boost::multiprecision::cpp_rational(boost::multiprecision::cpp_int(1), boost::multiprecision::cpp_int(boost::multiprecision::cpp_int(1) << 52));
// tie, but last bit is now a 1 so we round up:
BOOST_CHECK_NE(d, rat.convert_to<double>());
}
#endif
int main()
{
using namespace boost::multiprecision;
#if defined(TEST1) && !defined(BOOST_MSVC)
test_round_trip<number<cpp_bin_float<113, digit_base_2, void, boost::int16_t> >, cpp_rational>();
#elif defined(TEST2)
double_spot_tests();
test_round_trip<double, cpp_rational>();
#elif defined(TEST3) && !defined(BOOST_MSVC)
test_random_rationals<number<cpp_bin_float<113, digit_base_2, void, boost::int16_t> >, cpp_rational>();
#elif defined(TEST4)
test_random_rationals<double, cpp_rational>();
#elif defined(TEST5)
// This does not work: gmp does not correctly round integer to float or
// rational to float conversions:
test_round_trip<double, mpq_rational>();
#elif defined(TEST6)
test_round_trip<mpfr_float_100, mpq_rational>();
#elif defined(TEST7)
test_random_rationals<mpfr_float_100, mpq_rational>();
#elif defined(TEST8)
test_random_rationals<double, mpq_rational>();
#endif
return boost::report_errors();
}