anchor.diff:          v_com = sum(colloids%vel, dim=2)/colloids%Nmax
           call polar%update(com_pos, v_com, unit_r/norm2(unit_r), solvent, solvent_cells)
           call varia%tac()
  +
  +        if (do_quaternion) call omega_cf%add(i-equilibration_loops, correlate_block_dot, xvec=rigid_janus%omega_body)
  +
        end if
   
     end do
  
positive.code:   integer, dimension(N_species) :: n_solvent
    type(h5md_element_t) :: n_solvent_el
  
    type(h5md_element_t) :: q_el, janus_pos_el, janus_vel_el, u_el
  
    type(histogram_t) :: radial_hist
    type(h5md_element_t) :: radial_hist_el
  
negative.code:            call janus_io%position%append(colloids%pos)
             call janus_io%velocity%append(colloids%vel)
             call janus_io%image%append(colloids%image)
             call u_el%append(unit_r)
             if (do_quaternion) then
                call q_el%append(rigid_janus%q)
                call omega_body_el%append(rigid_janus%omega_body)
             end if
          end if
  
          call time_flag%tic()
  