bool resize_m_xnew_impl( const StateIn &x )
 {
     return adjust_size_by_resizeability( m_xnew , x , typename is_resizeable< wrapped_state_type >::type() );
 }
 bool resize_impl( const StateIn &x )
 {
     return adjust_size_by_resizeability( m_dxdt , x , typename is_resizeable<deriv_type>::type() );
 }
 bool resize_dpdt( const StateIn &x )
 {
     return adjust_size_by_resizeability( m_dpdt , x , typename is_resizeable<momentum_deriv_type>::type() );
 }