/// @brief Ordering relation used for maps etc.
///
/// Sorting on index and then orientation, with positive orientations first.
/// @param other The other entity representation.
/// @return true if \b this element is less than the \b other.
bool operator<(const EntityRep& other) const
{
int i1 = index();
int i2 = other.index();
if (i1 < i2) return true;
if (orientation() && !other.orientation()) return true;
return false;
}
/// @brief Random access to the variable through an EntityRep.
/// Note that this operator always returns a copy, not a
/// reference, since we may need to flip the sign.
const T operator[](const EntityRep<codim>& e) const
{
return e.orientation() ?
EntityVariableBase<T>::get(e.index()) :
-EntityVariableBase<T>::get(e.index());
}