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// (C) Copyright John Maddock 2014.
// 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)
#ifndef BOOST_MATH_TOOLS_MP_T
#define BOOST_MATH_TOOLS_MP_T
#ifndef BOOST_MATH_PRECISION
#define BOOST_MATH_PRECISION 1000
#endif
#if defined(BOOST_MATH_USE_MPFR)
#include <boost/multiprecision/mpfr.hpp>
typedef boost::multiprecision::number<boost::multiprecision::mpfr_float_backend<BOOST_MATH_PRECISION *301L / 1000L> > mp_t;
#else
#include <boost/multiprecision/cpp_bin_float.hpp>
typedef boost::multiprecision::number<boost::multiprecision::cpp_bin_float<BOOST_MATH_PRECISION, boost::multiprecision::digit_base_2> > mp_t;
#endif
inline mp_t ConvPrec(mp_t arg, int digits)
{
int e1, e2;
mp_t t = frexp(arg, &e1);
t = frexp(floor(ldexp(t, digits + 1)), &e2);
return ldexp(t, e1);
}
inline mp_t relative_error(mp_t a, mp_t b)
{
mp_t min_val = boost::math::tools::min_value<mp_t>();
mp_t max_val = boost::math::tools::max_value<mp_t>();
if((a != 0) && (b != 0))
{
// mp_tODO: use isfinite:
if(fabs(b) >= max_val)
{
if(fabs(a) >= max_val)
return 0; // one infinity is as good as another!
}
// If the result is denormalised, treat all denorms as equivalent:
if((a < min_val) && (a > 0))
a = min_val;
else if((a > -min_val) && (a < 0))
a = -min_val;
if((b < min_val) && (b > 0))
b = min_val;
else if((b > -min_val) && (b < 0))
b = -min_val;
return (std::max)(fabs((a - b) / a), fabs((a - b) / b));
}
// Handle special case where one or both are zero:
if(min_val == 0)
return fabs(a - b);
if(fabs(a) < min_val)
a = min_val;
if(fabs(b) < min_val)
b = min_val;
return (std::max)(fabs((a - b) / a), fabs((a - b) / b));
}
#endif // BOOST_MATH_TOOLS_MP_T
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