anchor.diff:  
     call h5open_f(error)
   
  -  L = [20, 20, 20]
  +  L = [32, 32, 32]
     N = rho *L(1)*L(2)*L(3)
     
     allocate(epsilon(2,2))
   
     epsilon = reshape((/ 1.d0, 1.d0, 1.d0, 0.5d0 /),shape(epsilon))
  -  sigma = 1
  +  sigma = 2.d0
     sigma_cut = sigma*2**(1.d0/6.d0)
   
     call solvent_colloid_lj% init( epsilon, &
          reshape( [ sigma, sigma, sigma, sigma ], [2, 2] ), reshape( [ sigma_cut,sigma_cut,sigma_cut,sigma_cut ], [2, 2] ) )
     
  -  epsilon1 = 1
  -  sigma = 1
  +  epsilon1 = 1.d0
  +  sigma = 2.d0
     sigma_cut = sigma*2**(1.d0/6.d0)
   
     call colloid_lj% init( reshape( [ epsilon1,epsilon1,epsilon1,epsilon1 ], [2, 2] ), &
  
positive.code:   double precision :: r(3) !old direction vector
    double precision :: d
    
    d  = sigma*2.d0 + 0.5d0!distance between the colloids in the dimer
  
    s = colloids% pos_old(:,1) - colloids% pos_old(:,2)
    r = pos_rattle(:,1) - pos_rattle(:,2)
  
negative.code:   type(lj_params_t) :: solvent_colloid_lj
    type(lj_params_t) :: colloid_lj
  
    integer, parameter :: rho = 9
    integer :: N
    integer :: error
    double precision, allocatable :: pos_rattle(:,:)
  