anchor.diff:     !---------------------------------------------
      ! Loop over time
      !---------------------------------------------
  -   do while (iter < maxiter)
  +   do while (t < maxtime)
   
         call integrate(v, a, dt/2)  ! Compute v(t+dt/2)
         call integrate(r, v, dt)    ! Compute r(t+dt)
  
positive.code:    real(kind = xp) :: E                 ! Total energy
     integer         :: iter      = 0     ! Number of iterations ran
     integer         :: dump_freq = 10    ! Frequency at which the system is sampled
     integer         :: maxiter   = 500   ! Maximum number of iterations
  
     !---------------------------------------------
     ! Read initial positions
  
negative.code:    print *, '# Simulation parameters'
     print *, '# dt', dt
     print *, '# npoints', npoints
     print *, '# maxtime', maxtime
  
     !---------------------------------------------
     ! Open files for output, add headers
  