anchor.diff:    colloids% force_old = colloids% force
   
     call h5fflush_f(hfile%id, H5F_SCOPE_GLOBAL_F, error)
  +
  +  write(*,*) 'Box size', L
  +  write(*,*) N, 'fluid particles'
  +
     write(*,*) 'Running for', equilibration_loops, '+', N_loop, 'loops'
   
     call main%tic()
  
positive.code: 
    sigma_E = PTread_d(config, 'sigma_E', loc=params_group)
    sigma_N = PTread_d(config, 'sigma_N', loc=params_group)
  
    ! solvent index first, colloid index second, in solvent_colloid_lj
    epsilon(:,1) = PTread_dvec(config, 'epsilon_E', 3, loc=params_group)
  
negative.code: 
    L = PTread_ivec(config, 'L', 3, loc=params_group)
    rho = PTread_i(config, 'rho', loc=params_group)
  
    T = PTread_d(config, 'T', loc=params_group)
    link_d = PTread_dvec(config, 'link_d', 2, loc=params_group)
  