anchor.diff:    type(lj_params_t) :: colloid_lj
     type(lj_params_t) :: walls_colloid_lj
   
  -  type(profile_t) :: tz
  -  type(histogram_t) :: rhoz
     type(profile_t) :: vx
   
     integer :: rho
  
positive.code:   call solvent_cells%init(L, 1.d0,has_walls = .true.)
  
    colloids% pos(3,:) = solvent_cells% edges(3)/2.d0
    order = .false.!PTread_l(config, 'order')
    if (order) then
       colloids% pos(1,1) = sigma_C*2**(1.d0/6.d0)+0.1d0
       colloids% pos(1,2) = colloids% pos(1,1) + d
       colloids% pos(2,:) = solvent_cells% edges(2)/2.d0 + 1.5d0*maxval([sigma_C,sigma_N])
    else
       colloids% pos(1,2) = sigma_N*2**(1.d0/6.d0)+0.1d0
       colloids% pos(1,1) = colloids% pos(1,2) + d
       colloids% pos(2,:) = solvent_cells% edges(2)/2.d0 + 1.5d0*maxval([sigma_C,sigma_N])
    end if
  
negative.code:   integer(HID_T) :: box_group
  
    type(PTo) :: config
    integer :: i, L(3),  n_threads
    integer :: j, k, m
    
  