anchor.diff:  
     subroutine flag_particles
       double precision :: dist_to_C_sq
  -    integer :: i, r, s, thread_id
  +    integer :: i, r, s
       double precision :: x(3)
   
  -    !$omp parallel private(thread_id)
  -    thread_id = omp_get_thread_num() + 1
  +    !$omp parallel
       !$omp do private(i, s, r, x, dist_to_C_sq)
       do i = 1, colloids%Nmax
          if (colloids%species(i)==1) then
  
positive.code:   if (do_read_links) links_file = PTread_s(config, 'links_file', loc=params_group)
  
    polar_r_max = PTread_d(config, 'polar_r_max', loc=params_group)
  
    call h5gclose_f(params_group, error)
    call PTkill(config)
  
negative.code:         if (do_quaternion) then
             call rigid_janus%compute_force_torque(colloids)
             call rigid_janus%vv2(colloids, dt)
          else if (do_rattle) then
             call varia%tic()
             do k = 1, colloids%Nmax
                colloids% vel(:,k) = colloids% vel(:,k) + &
  