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///////////////////////////////////////////////////////////////
// Copyright 2012 - 2025 John Maddock.
// Copyright 2025 Christopher Kormanyos.
// 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
//
#ifdef _MSC_VER
#define _SCL_SECURE_NO_WARNINGS
#endif
#include <test.hpp>
#include <boost/detail/lightweight_test.hpp>
#include <boost/multiprecision/cpp_bin_float.hpp>
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int.hpp>
#include <array>
#include <cstdint>
template <class T>
T generate_random()
{
typedef int 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 boost::random::uniform_int_distribution<e_type> ui(-20, 20);
return ldexp(val, ui(gen));
}
template <class T>
void check_round(const T& val, bool check_extended = false)
{
double d1 = val.template convert_to<double>();
double d2 = boost::math::nextafter(d1, d1 < val ? DBL_MAX : -DBL_MAX);
T diff1 = abs(d1 - val);
T diff2 = abs(d2 - val);
if (diff2 < diff1)
{
// Some debugging code here...
// LCOV_EXCL_START These lines are not expected to get hit in tests.
std::cout << val.str() << std::endl;
std::cout << std::setprecision(18);
std::cout << d1 << std::endl;
std::cout << d2 << std::endl;
std::cout << diff1 << std::endl;
std::cout << diff2 << std::endl;
d1 = val.template convert_to<double>();
// LCOV_EXCL_STOP These lines are not expected to get hit in tests.
}
using std::signbit;
BOOST_CHECK(diff2 >= diff1);
// Note: Ask John if boost::multiprecision::signbit() should return bool?
BOOST_CHECK_EQUAL((boost::math::signbit(val) != 0), signbit(d1));
float f1 = val.template convert_to<float>();
float f2 = boost::math::nextafter(f1, f1 < val ? FLT_MAX : -FLT_MAX);
BOOST_CHECK(((abs(f1 - val) <= abs(f2 - val))));
BOOST_CHECK_EQUAL((boost::math::signbit(val) != 0), signbit(f1));
#if !defined(BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS)
if (check_extended)
{
//
// We should check long double as well:
//
long double l1 = val.template convert_to<long double>();
long double l2 = boost::math::nextafter(d1, d1 < val ? LDBL_MAX : -LDBL_MAX);
diff1 = abs(l1 - val);
diff2 = abs(l2 - val);
if (diff2 < diff1)
{
// Some debugging code here...
// LCOV_EXCL_START These lines are not expected to get hit in tests.
std::cout << val.str() << std::endl;
std::cout << std::setprecision(18);
std::cout << l1 << std::endl;
std::cout << l2 << std::endl;
std::cout << diff1 << std::endl;
std::cout << diff2 << std::endl;
l1 = val.template convert_to<long double>();
// LCOV_EXCL_STOP These lines are not expected to get hit in tests.
}
BOOST_CHECK(diff2 >= diff1);
BOOST_CHECK_EQUAL((boost::math::signbit(val) != 0), signbit(l1));
}
#endif
}
int main()
{
using namespace boost::multiprecision;
cpp_int i(20);
cpp_bin_float_50 f50(i);
BOOST_CHECK_EQUAL(f50, 20);
f50 = i.convert_to<cpp_bin_float_50>();
BOOST_CHECK_EQUAL(f50, 20);
int1024_t i1024(45);
cpp_bin_float_100 f100(i1024);
BOOST_CHECK_EQUAL(f100, 45);
f100 = i1024.convert_to<cpp_bin_float_100>();
BOOST_CHECK_EQUAL(f100, 45);
uint1024_t ui1024(55);
cpp_bin_float_100 f100b(ui1024);
BOOST_CHECK_EQUAL(f100b, 55);
f100b = ui1024.convert_to<cpp_bin_float_100>();
BOOST_CHECK_EQUAL(f100b, 55);
typedef number<cpp_int_backend<32, 32>, et_off> i32_t;
i32_t i32(67);
cpp_bin_float_100 f100c(i32);
BOOST_CHECK_EQUAL(f100c, 67);
f100c = i32.convert_to<cpp_bin_float_100>();
BOOST_CHECK_EQUAL(f100c, 67);
typedef number<cpp_int_backend<32, 32, unsigned_magnitude>, et_off> ui32_t;
ui32_t ui32(98);
cpp_bin_float_100 f100d(ui32);
BOOST_CHECK_EQUAL(f100d, 98);
f100d = ui32.convert_to<cpp_bin_float_100>();
BOOST_CHECK_EQUAL(f100d, 98);
typedef number<cpp_int_backend<64, 64>, et_off> i64_t;
i64_t i64(67);
cpp_bin_float_100 f100e(i64);
BOOST_CHECK_EQUAL(f100e, 67);
f100e = i64.convert_to<cpp_bin_float_100>();
BOOST_CHECK_EQUAL(f100e, 67);
typedef number<cpp_int_backend<64, 64, unsigned_magnitude>, et_off> ui64_t;
ui64_t ui64(98);
cpp_bin_float_100 f100f(ui64);
BOOST_CHECK_EQUAL(f100f, 98);
f100f = ui64.convert_to<cpp_bin_float_100>();
BOOST_CHECK_EQUAL(f100f, 98);
typedef number<cpp_int_backend<128, 128>, et_off> i128_t;
i128_t i128(67);
cpp_bin_float_100 f100g(i128);
BOOST_CHECK_EQUAL(f100g, 67);
f100g = i128.convert_to<cpp_bin_float_100>();
BOOST_CHECK_EQUAL(f100g, 67);
typedef number<cpp_int_backend<128, 128, unsigned_magnitude>, et_off> ui128_t;
ui128_t ui128(98);
cpp_bin_float_100 f100h(ui128);
BOOST_CHECK_EQUAL(f100h, 98);
f100h = ui128.convert_to<cpp_bin_float_100>();
BOOST_CHECK_EQUAL(f100h, 98);
cpp_bin_float_quad q = (std::numeric_limits<float>::min)();
BOOST_CHECK_EQUAL(q.convert_to<float>(), (std::numeric_limits<float>::min)());
q = (std::numeric_limits<float>::max)();
BOOST_CHECK_EQUAL(q.convert_to<float>(), (std::numeric_limits<float>::max)());
q = (std::numeric_limits<float>::denorm_min)();
BOOST_CHECK_EQUAL(q.convert_to<float>(), (std::numeric_limits<float>::denorm_min)());
// See https://svn.boost.org/trac/boost/ticket/12512:
boost::multiprecision::number<boost::multiprecision::backends::cpp_bin_float<128, boost::multiprecision::backends::digit_base_2, void, std::int64_t> > ext_float("1e-646456978");
BOOST_CHECK_EQUAL(ext_float.convert_to<float>(), 0);
q = -(std::numeric_limits<float>::min)();
BOOST_CHECK_EQUAL(q.convert_to<float>(), -(std::numeric_limits<float>::min)());
q = -(std::numeric_limits<float>::max)();
BOOST_CHECK_EQUAL(q.convert_to<float>(), -(std::numeric_limits<float>::max)());
q = -(std::numeric_limits<float>::denorm_min)();
BOOST_CHECK_EQUAL(q.convert_to<float>(), -(std::numeric_limits<float>::denorm_min)());
// See https://svn.boost.org/trac/boost/ticket/12512:
ext_float = boost::multiprecision::number<boost::multiprecision::backends::cpp_bin_float<128, boost::multiprecision::backends::digit_base_2, void, std::int64_t> >("-1e-646456978");
BOOST_CHECK_EQUAL(ext_float.convert_to<float>(), 0);
ext_float = (std::numeric_limits<double>::max)();
ext_float *= 16;
if (std::numeric_limits<double>::has_infinity)
{
BOOST_CHECK_EQUAL(ext_float.convert_to<double>(), std::numeric_limits<double>::infinity());
}
else
{
BOOST_CHECK_EQUAL(ext_float.convert_to<double>(), (std::numeric_limits<double>::max)());
}
ext_float = -ext_float;
if (std::numeric_limits<double>::has_infinity)
{
BOOST_CHECK_EQUAL(ext_float.convert_to<double>(), -std::numeric_limits<double>::infinity());
}
else
{
BOOST_CHECK_EQUAL(ext_float.convert_to<double>(), -(std::numeric_limits<double>::max)());
}
//
// Check for double rounding when the result would be a denorm.
// See https://svn.boost.org/trac/boost/ticket/12527
//
cpp_bin_float_50 r1 = ldexp(cpp_bin_float_50(0x8000000000000bffull), -63 - 1023);
check_round(r1);
r1 = -r1;
check_round(r1);
r1 = ldexp(cpp_bin_float_50(0x8000017f), -31 - 127);
check_round(r1);
r1 = -r1;
check_round(r1);
//
// Check conversion to signed zero works OK:
//
r1 = -ldexp(cpp_bin_float_50(1), -3000);
check_round(r1);
r1 = 0;
r1 = -r1;
BOOST_CHECK(boost::math::signbit(r1));
check_round(r1);
//
// Check boundary as the exponent drops below what a double can cope with
// but we will be rounding up:
//
r1 = 3;
r1 = ldexp(r1, std::numeric_limits<double>::min_exponent);
do
{
check_round(r1);
check_round(boost::math::float_next(r1));
check_round(boost::math::float_prior(r1));
r1 = ldexp(r1, -1);
} while (ilogb(r1) > std::numeric_limits<double>::min_exponent - 5 - std::numeric_limits<double>::digits);
r1 = -3;
r1 = ldexp(r1, std::numeric_limits<double>::min_exponent);
do
{
check_round(r1);
check_round(boost::math::float_next(r1));
check_round(boost::math::float_prior(r1));
r1 = ldexp(r1, -1);
} while (ilogb(r1) > std::numeric_limits<double>::min_exponent - 5 - std::numeric_limits<double>::digits);
//
// Again when not rounding up:
//
r1 = 1;
r1 = ldexp(r1, std::numeric_limits<double>::min_exponent);
do
{
check_round(r1);
check_round(boost::math::float_next(r1));
check_round(boost::math::float_prior(r1));
r1 = ldexp(r1, -1);
} while (ilogb(r1) > std::numeric_limits<double>::min_exponent - 5 - std::numeric_limits<double>::digits);
r1 = -1;
r1 = ldexp(r1, std::numeric_limits<double>::min_exponent);
do
{
check_round(r1);
check_round(boost::math::float_next(r1));
check_round(boost::math::float_prior(r1));
r1 = ldexp(r1, -1);
} while (ilogb(r1) > std::numeric_limits<double>::min_exponent - 5 - std::numeric_limits<double>::digits);
//
// Test random conversions:
//
for (unsigned j = 0; j < 10000; ++j)
{
check_round(generate_random<cpp_bin_float_50>(), true);
}
return boost::report_errors();
}
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