anchor.diff:    dimer_io%id_info%store = .false.
     dimer_io%position_info%store = .true.
     dimer_io%position_info%mode = ior(H5MD_LINEAR,H5MD_STORE_TIME)
  -  dimer_io%position_info%step = N_MD_steps
  -  dimer_io%position_info%time = N_MD_steps*dt
  +  dimer_io%position_info%step = colloid_sampling
  +  dimer_io%position_info%time = colloid_sampling*dt
     dimer_io%image_info%store = .true.
     dimer_io%image_info%mode = ior(H5MD_LINEAR,H5MD_STORE_TIME)
  -  dimer_io%image_info%step = N_MD_steps
  -  dimer_io%image_info%time = N_MD_steps*dt
  +  dimer_io%image_info%step = colloid_sampling
  +  dimer_io%image_info%time = colloid_sampling*dt
     dimer_io%velocity_info%store = .true.
     dimer_io%velocity_info%mode = ior(H5MD_LINEAR,H5MD_STORE_TIME)
  -  dimer_io%velocity_info%step = N_MD_steps
  -  dimer_io%velocity_info%time = N_MD_steps*dt
  +  dimer_io%velocity_info%step = colloid_sampling
  +  dimer_io%velocity_info%time = colloid_sampling*dt
     dimer_io%species_info%store = .true.
     dimer_io%species_info%mode = H5MD_FIXED
     call dimer_io%init(hfile, 'dimer', colloids)
  
positive.code: !! \param tau              MPCD collision time
  !! \param N_MD_steps       number MD steps occuring in tau
  !! \param N_loop           number of MPCD timesteps
  !! \param steps_fixed      number of steps during which the colloid is fixed
  !! \param sigma_C          radius of C sphere
  !! \param sigma_N          radius of N sphere
  
negative.code:   double precision :: d,prob
    double precision :: skin, co_max, so_max
    integer :: N_MD_steps, N_loop
    integer :: colloid_sampling
    integer :: n_extra_sorting
    double precision :: kin_e, temperature
    integer, dimension(N_species) :: n_solvent, catalytic_change, bulk_change
  