anchor.diff:          ! Note that population and tot_population refer to a single 'type' of
           ! population, i.e. either a set of Hamiltonian walkers or a set of
           ! Hellmann--Feynman walkers.
  +        !      ___
  +        !     / _ \
  +        !    | / \ |
  +        !     \\.//
  +
   
   
           use death, only: stochastic_death
  
positive.code:         !        and the child determinant, on which progeny are spawned.
          use determinants, only: det_info
          use excitations, only: excit
          use fciqmc_data, only: tau
          use excitations, only: create_excited_det_complete
  
          type(det_info), intent(in) :: cdet
  
negative.code:             connection%nexcit = connection_ki%nexcit + connection_jk%nexcit
              ! (ii)  combine the annihilations
              connection%from_orb(:connection_ki%nexcit) = &
                                  connection_ki%from_orb(:connection_ki%nexcit)
  
              connection%from_orb(connection_ki%nexcit+1:connection%nexcit) = &
                                  connection_jk%from_orb(:connection_jk%nexcit)
  
              ! (iii) combine the creations
              connection%to_orb(:connection_ki%nexcit) = &
  