template<class T, class Policies> inline
interval<T, Policies> operator*(const interval<T, Policies>& x,
const interval<T, Policies>& y)
{
BOOST_USING_STD_MIN();
BOOST_USING_STD_MAX();
typedef interval<T, Policies> I;
if (interval_lib::detail::test_input(x, y))
return I::empty();
typename Policies::rounding rnd;
const T& xl = x.lower();
const T& xu = x.upper();
const T& yl = y.lower();
const T& yu = y.upper();
if (interval_lib::user::is_neg(xl))
if (interval_lib::user::is_pos(xu))
if (interval_lib::user::is_neg(yl))
if (interval_lib::user::is_pos(yu)) // M * M
return I(min BOOST_PREVENT_MACRO_SUBSTITUTION(rnd.mul_down(xl, yu), rnd.mul_down(xu, yl)),
max BOOST_PREVENT_MACRO_SUBSTITUTION(rnd.mul_up (xl, yl), rnd.mul_up (xu, yu)), true);
else // M * N
return I(rnd.mul_down(xu, yl), rnd.mul_up(xl, yl), true);
else
if (interval_lib::user::is_pos(yu)) // M * P
return I(rnd.mul_down(xl, yu), rnd.mul_up(xu, yu), true);
else // M * Z
return I(static_cast<T>(0), static_cast<T>(0), true);
else
if (interval_lib::user::is_neg(yl))
if (interval_lib::user::is_pos(yu)) // N * M
return I(rnd.mul_down(xl, yu), rnd.mul_up(xl, yl), true);
else // N * N
return I(rnd.mul_down(xu, yu), rnd.mul_up(xl, yl), true);
else
if (interval_lib::user::is_pos(yu)) // N * P
return I(rnd.mul_down(xl, yu), rnd.mul_up(xu, yl), true);
else // N * Z
return I(static_cast<T>(0), static_cast<T>(0), true);
else
if (interval_lib::user::is_pos(xu))
if (interval_lib::user::is_neg(yl))
if (interval_lib::user::is_pos(yu)) // P * M
return I(rnd.mul_down(xu, yl), rnd.mul_up(xu, yu), true);
else // P * N
return I(rnd.mul_down(xu, yl), rnd.mul_up(xl, yu), true);
else
if (interval_lib::user::is_pos(yu)) // P * P
return I(rnd.mul_down(xl, yl), rnd.mul_up(xu, yu), true);
else // P * Z
return I(static_cast<T>(0), static_cast<T>(0), true);
else // Z * ?
return I(static_cast<T>(0), static_cast<T>(0), true);
}
template<class T, class Policies> inline
interval<T, Policies> operator*(const interval<T, Policies>& x,
const interval<T, Policies>& y)
{
BOOST_NUMERIC_INTERVAL_using_max(min);
BOOST_NUMERIC_INTERVAL_using_max(max);
typedef interval<T, Policies> I;
if (interval_lib::detail::test_input(x, y))
return I::empty();
typename Policies::rounding rnd;
const T& xl = x.lower();
const T& xu = x.upper();
const T& yl = y.lower();
const T& yu = y.upper();
if (interval_lib::detail::is_neg(xl))
if (interval_lib::detail::is_pos(xu))
if (interval_lib::detail::is_neg(yl))
if (interval_lib::detail::is_pos(yu)) // M * M
return I(min(rnd.mul_down(xl, yu), rnd.mul_down(xu, yl)),
max(rnd.mul_up (xl, yl), rnd.mul_up (xu, yu)), true);
else // M * N
return I(rnd.mul_down(xu, yl), rnd.mul_up(xl, yl), true);
else
if (interval_lib::detail::is_pos(yu)) // M * P
return I(rnd.mul_down(xl, yu), rnd.mul_up(xu, yu), true);
else // M * Z
return I(0, 0, true);
else
if (interval_lib::detail::is_neg(yl))
if (interval_lib::detail::is_pos(yu)) // N * M
return I(rnd.mul_down(xl, yu), rnd.mul_up(xl, yl), true);
else // N * N
return I(rnd.mul_down(xu, yu), rnd.mul_up(xl, yl), true);
else
if (interval_lib::detail::is_pos(yu)) // N * P
return I(rnd.mul_down(xl, yu), rnd.mul_up(xu, yl), true);
else // N * Z
return I(0, 0, true);
else
if (interval_lib::detail::is_pos(xu))
if (interval_lib::detail::is_neg(yl))
if (interval_lib::detail::is_pos(yu)) // P * M
return I(rnd.mul_down(xu, yl), rnd.mul_up(xu, yu), true);
else // P * N
return I(rnd.mul_down(xu, yl), rnd.mul_up(xl, yu), true);
else
if (interval_lib::detail::is_pos(yu)) // P * P
return I(rnd.mul_down(xl, yl), rnd.mul_up(xu, yu), true);
else // P * Z
return I(0, 0, true);
else // Z * ?
return I(0, 0, true);
}
template<class T, class Policies> inline
interval<T, Policies> operator*(const T& x, const interval<T, Policies>& y)
{
typedef interval<T, Policies> I;
if (interval_lib::detail::test_input(x, y))
return I::empty();
typename Policies::rounding rnd;
const T& yl = y.lower();
const T& yu = y.upper();
// x is supposed not to be infinite
if (interval_lib::user::is_neg(x))
return I(rnd.mul_down(x, yu), rnd.mul_up(x, yl), true);
else if (interval_lib::user::is_zero(x))
return I(static_cast<T>(0), static_cast<T>(0), true);
else
return I(rnd.mul_down(x, yl), rnd.mul_up(x, yu), true);
}
template<class I> inline
I mul(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.mul_down(x, y), rnd.mul_up(x, y), true);
}