template<class T, class Policies> inline
T width(const interval<T, Policies>& x)
{
if (interval_lib::detail::test_input(x)) return static_cast<T>(0);
typename Policies::rounding rnd;
return rnd.sub_up(x.upper(), x.lower());
}
template<class I> inline
I sub(const typename I::base_type& x, const typename I::base_type& y)
{
typedef typename I::traits_type Policies;
if (detail::test_input<typename I::base_type, Policies>(x, y))
return I::empty();
typename Policies::rounding rnd;
return I(rnd.sub_down(x, y), rnd.sub_up(x, y), true);
}
template<class T, class Policies> inline
interval<T, Policies> operator-(const interval<T, Policies>& x, const T& y)
{
if (interval_lib::detail::test_input(x, y))
return interval<T, Policies>::empty();
typename Policies::rounding rnd;
return interval<T,Policies>(rnd.sub_down(x.lower(), y),
rnd.sub_up (x.upper(), y), true);
}
template<class T, class Policies> inline
interval<T, Policies>& interval<T, Policies>::operator-=(const T& r)
{
if (interval_lib::detail::test_input(*this, r))
set_empty();
else {
typename Policies::rounding rnd;
set(rnd.sub_down(low, r), rnd.sub_up(up, r));
}
return *this;
}