anchor.diff:                                                       sys%max_number_excitations, weighted_sampling)
   
                   end do
  + 
   
                   ! Sum all quantities being considered across all MPI processes.
                   error = qs%spawn_store%spawn%error .or. qs%psip_list%error .or. rdm_error
  
positive.code:                         ! Quasi-Newton not yet implemented -- see also stochastic_death call.
                          cdet1%fock_sum = 1.0_p
                          cdet2%fock_sum = 1.0_p
  
                          ! If using multiple symmetry sectors then find the
                          ! symmetry labels of this particular det.
                          if (dmqmc_in%all_spin_sectors) call update_sys_spin_info(cdet1, sys)
  
negative.code:                     if (dmqmc_in%ipdmqmc .and. dmqmc_in%symmetric) &
                              & weighted_sampling%probs(sys%max_number_excitations+1) = &
                              & 0.5*(qs%target_beta-(iteration-1)*qs%dmqmc_factor*qs%tau)
  
  
                      do idet = 1, qs%psip_list%nstates ! loop over walkers/dets
  
  