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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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