anchor.diff:  
     call h5fflush_f(hfile%id, H5F_SCOPE_GLOBAL_F, error)
     write(*,*) 'Running for', equilibration_loops, '+', N_loop, 'loops'
  -  write(*,*) 'mass', mass 
  +
     call main%tic()
     sampling = .false.
     enzyme_bound = .false.
  -  next_reaction_time = huge(next_reaction_time)
  +  next_reaction_time = huge(next_reaction_time(1))
   
     do i = 0, N_loop+equilibration_loops
        if (i==equilibration_loops) sampling = .true.
  
positive.code:            unit_r = rel_pos(colloids%pos(:,1), colloids%pos(:,2), solvent_cells%edges)
             unit_r = unit_r / norm2(unit_r)
             call axial_cf%add_fast((i-equilibration_loops)*N_MD_steps+j-1, v_com, unit_r)
          end if
  
          if ((sampling) .and. (modulo(j, colloid_sampling)==0)) then
  
negative.code:            end if
          end do
          do k = 1, colloids%Nmax
             v_com = v_com + colloids%mass(k) * colloids%vel(:,k)
             kin_e = kin_e + colloids%mass(k) * sum(colloids%vel(:,k)**2) / 2
          end do
  
          call thermo_data%append(hfile, temperature, e1+e2+e3, kin_e, e1+e2+e3+kin_e, v_com)
  
          ! todo: decide what to do with sampling
          com_pos = colloids%pos(:,2)
          call axial_cf%add(i-equilibration_loops, com_pos, unit_r)
  
       end if
  
       call varia%tac()
  
       if (sampling) then
          n_solvent = 0
  