anchor.diff:  
       function spawning_rate(ndeath, nattempts) result(rate)
   
  -        use parallel, only: nprocs
  -
           ! Calculate the rate of spawning on the current processor.
           ! In:
           !    ndeath: number of particles that were killed/cloned during the MC
  
positive.code:         !   (nspawn + ndeath) / nattempts
          ! In the timestep algorithm each particle has 2 attempts (one to spawn on a different
          ! determinant and one to clone/die).
          rate = real(nspawn+ndeath,p)/nattempts
  
      end function spawning_rate
  
  
negative.code:         !    processor at the beginning of the Monte Carlo cycle (multiplied by
          !    2 for the timestep algorithm).
  
          use parallel, only: nprocs
  
          real(p) :: rate
          integer, intent(in) :: ndeath
          integer(lint), intent(in) :: nattempts
  