const T & operator()(unsigned int i) const
class handling particles (position only)
T & operator()(unsigned int i)
class handling particles (position only)
const T & operator[](unsigned int i) const
Particle_v(Vec_3D< U > position, Vec_3D< V > velocity)
Particle_x(Vec_3D< U > position)
T & operator[](unsigned int i)
get position coordinates