195 lines
7.5 KiB
C++
195 lines
7.5 KiB
C++
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/* Boost interval/detail/division.hpp file
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*
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* Copyright 2003 Guillaume Melquiond, Sylvain Pion
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*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or
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* copy at http://www.boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_NUMERIC_INTERVAL_DETAIL_DIVISION_HPP
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#define BOOST_NUMERIC_INTERVAL_DETAIL_DIVISION_HPP
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#include <boost/numeric/interval/detail/interval_prototype.hpp>
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#include <boost/numeric/interval/detail/bugs.hpp>
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#include <boost/numeric/interval/detail/test_input.hpp>
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#include <boost/numeric/interval/rounded_arith.hpp>
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#include <algorithm>
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namespace boost {
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namespace numeric {
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namespace interval_lib {
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namespace detail {
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template<class T, class Policies> inline
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interval<T, Policies> div_non_zero(const interval<T, Policies>& x,
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const interval<T, Policies>& y)
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{
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// assert(!in_zero(y));
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typename Policies::rounding rnd;
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typedef interval<T, Policies> I;
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const T& xl = x.lower();
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const T& xu = x.upper();
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const T& yl = y.lower();
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const T& yu = y.upper();
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if (::boost::numeric::interval_lib::user::is_neg(xu))
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if (::boost::numeric::interval_lib::user::is_neg(yu))
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return I(rnd.div_down(xu, yl), rnd.div_up(xl, yu), true);
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else
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return I(rnd.div_down(xl, yl), rnd.div_up(xu, yu), true);
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else if (::boost::numeric::interval_lib::user::is_neg(xl))
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if (::boost::numeric::interval_lib::user::is_neg(yu))
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return I(rnd.div_down(xu, yu), rnd.div_up(xl, yu), true);
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else
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return I(rnd.div_down(xl, yl), rnd.div_up(xu, yl), true);
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else
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if (::boost::numeric::interval_lib::user::is_neg(yu))
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return I(rnd.div_down(xu, yu), rnd.div_up(xl, yl), true);
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else
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return I(rnd.div_down(xl, yu), rnd.div_up(xu, yl), true);
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_non_zero(const T& x, const interval<T, Policies>& y)
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{
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// assert(!in_zero(y));
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typename Policies::rounding rnd;
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typedef interval<T, Policies> I;
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const T& yl = y.lower();
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const T& yu = y.upper();
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if (::boost::numeric::interval_lib::user::is_neg(x))
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return I(rnd.div_down(x, yl), rnd.div_up(x, yu), true);
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else
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return I(rnd.div_down(x, yu), rnd.div_up(x, yl), true);
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_positive(const interval<T, Policies>& x, const T& yu)
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{
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// assert(::boost::numeric::interval_lib::user::is_pos(yu));
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if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
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::boost::numeric::interval_lib::user::is_zero(x.upper()))
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return x;
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typename Policies::rounding rnd;
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typedef interval<T, Policies> I;
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const T& xl = x.lower();
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const T& xu = x.upper();
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typedef typename Policies::checking checking;
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if (::boost::numeric::interval_lib::user::is_neg(xu))
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return I(checking::neg_inf(), rnd.div_up(xu, yu), true);
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else if (::boost::numeric::interval_lib::user::is_neg(xl))
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return I(checking::neg_inf(), checking::pos_inf(), true);
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else
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return I(rnd.div_down(xl, yu), checking::pos_inf(), true);
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_positive(const T& x, const T& yu)
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{
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// assert(::boost::numeric::interval_lib::user::is_pos(yu));
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typedef interval<T, Policies> I;
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if (::boost::numeric::interval_lib::user::is_zero(x))
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return I(static_cast<T>(0), static_cast<T>(0), true);
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typename Policies::rounding rnd;
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typedef typename Policies::checking checking;
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if (::boost::numeric::interval_lib::user::is_neg(x))
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return I(checking::neg_inf(), rnd.div_up(x, yu), true);
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else
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return I(rnd.div_down(x, yu), checking::pos_inf(), true);
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_negative(const interval<T, Policies>& x, const T& yl)
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{
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// assert(::boost::numeric::interval_lib::user::is_neg(yl));
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if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
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::boost::numeric::interval_lib::user::is_zero(x.upper()))
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return x;
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typename Policies::rounding rnd;
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typedef interval<T, Policies> I;
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const T& xl = x.lower();
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const T& xu = x.upper();
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typedef typename Policies::checking checking;
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if (::boost::numeric::interval_lib::user::is_neg(xu))
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return I(rnd.div_down(xu, yl), checking::pos_inf(), true);
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else if (::boost::numeric::interval_lib::user::is_neg(xl))
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return I(checking::neg_inf(), checking::pos_inf(), true);
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else
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return I(checking::neg_inf(), rnd.div_up(xl, yl), true);
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_negative(const T& x, const T& yl)
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{
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// assert(::boost::numeric::interval_lib::user::is_neg(yl));
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typedef interval<T, Policies> I;
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if (::boost::numeric::interval_lib::user::is_zero(x))
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return I(static_cast<T>(0), static_cast<T>(0), true);
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typename Policies::rounding rnd;
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typedef typename Policies::checking checking;
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if (::boost::numeric::interval_lib::user::is_neg(x))
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return I(rnd.div_down(x, yl), checking::pos_inf(), true);
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else
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return I(checking::neg_inf(), rnd.div_up(x, yl), true);
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_zero(const interval<T, Policies>& x)
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{
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if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
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::boost::numeric::interval_lib::user::is_zero(x.upper()))
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return x;
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else return interval<T, Policies>::whole();
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_zero(const T& x)
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{
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if (::boost::numeric::interval_lib::user::is_zero(x))
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return interval<T, Policies>(static_cast<T>(0), static_cast<T>(0), true);
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else return interval<T, Policies>::whole();
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_zero_part1(const interval<T, Policies>& x,
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const interval<T, Policies>& y, bool& b)
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{
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// assert(::boost::numeric::interval_lib::user::is_neg(y.lower()) && ::boost::numeric::interval_lib::user::is_pos(y.upper()));
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if (::boost::numeric::interval_lib::user::is_zero(x.lower()) && ::boost::numeric::interval_lib::user::is_zero(x.upper()))
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{ b = false; return x; }
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typename Policies::rounding rnd;
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typedef interval<T, Policies> I;
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const T& xl = x.lower();
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const T& xu = x.upper();
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const T& yl = y.lower();
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const T& yu = y.upper();
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typedef typename Policies::checking checking;
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if (::boost::numeric::interval_lib::user::is_neg(xu))
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{ b = true; return I(checking::neg_inf(), rnd.div_up(xu, yu), true); }
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else if (::boost::numeric::interval_lib::user::is_neg(xl))
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{ b = false; return I(checking::neg_inf(), checking::pos_inf(), true); }
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else
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{ b = true; return I(checking::neg_inf(), rnd.div_up(xl, yl), true); }
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}
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template<class T, class Policies> inline
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interval<T, Policies> div_zero_part2(const interval<T, Policies>& x,
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const interval<T, Policies>& y)
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{
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// assert(::boost::numeric::interval_lib::user::is_neg(y.lower()) && ::boost::numeric::interval_lib::user::is_pos(y.upper()) && (div_zero_part1(x, y, b), b));
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typename Policies::rounding rnd;
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typedef interval<T, Policies> I;
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typedef typename Policies::checking checking;
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if (::boost::numeric::interval_lib::user::is_neg(x.upper()))
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return I(rnd.div_down(x.upper(), y.lower()), checking::pos_inf(), true);
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else
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return I(rnd.div_down(x.lower(), y.upper()), checking::pos_inf(), true);
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}
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} // namespace detail
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} // namespace interval_lib
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} // namespace numeric
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} // namespace boost
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#endif // BOOST_NUMERIC_INTERVAL_DETAIL_DIVISION_HPP
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