anchor.diff:       if (block_length**n_blocks >= N_loop*N_MD_steps/block_length) exit
     end do
     call vacf%init(block_length, n_blocks, dim=3)
  +  call parallel_vacf%init(block_length, n_blocks, dim=3)
  +  call transverse_vacf%init(block_length, n_blocks, dim=3)
   
     if (dimer) then
        colloids% species(1) = 1
  
positive.code: 
    integer, parameter :: block_length = 8
    integer :: n_blocks
    type(correlator_t) :: msd, omega_acf, oacf, vacf
    integer(HID_T) :: correlator_group, group
  
    double precision :: unit_r(3), omega(3), rel_v(3), norm_xy
  
  
negative.code: 
    end subroutine compute_rho_xy
  
    subroutine write_correlator_block(loc, name, c, step, time)
      integer(HID_T), intent(inout) :: loc
      character(len=*), intent(in) :: name
      type(correlator_t), intent(in) :: c
      integer, intent(in) :: step
      double precision, intent(in) :: time
  
      integer(HID_T) :: group
      integer :: error
  
      call h5gcreate_f(loc, name, group, error)
      call h5md_write_dataset(group, 'value', c%correlation)
      call h5md_write_dataset(group, 'count', c%count)
      call h5md_write_dataset(group, 'step', step)
      call h5md_write_dataset(group, 'time', time)
      call h5gclose_f(group, error)
  
    end subroutine write_correlator_block
  
  end program chemotactic_cell
  