anchor.diff:  
           do idet = 1, spawn%head(0,0) ! loop over walkers/dets
   
  -            pop = int(spawn%sdata(spawn%bit_str_len+1:spawn%bit_str_len+spawn%ntypes, idet), int_p)
  +            int_pop = int(spawn%sdata(spawn%bit_str_len+1:spawn%bit_str_len+spawn%ntypes, idet), int_p)
  +            real_pop = real(int_pop(1),p) / real_factor
               ftmp = int(spawn%sdata(:sys%basis%tensor_label_len,idet),i0)
               ! Need to generate spawned walker data to perform evolution.
               tmp_data(1) = sc0_ptr(sys, cdet%f) - H00
  
positive.code: 
              ! Clone or die.
              ! list_pop is meaningless as nparticles is updated upon annihilation.
              call stochastic_death(rng, tmp_data(1), shift(1), pop(1), list_pop, ndeath)
              ! Update population of walkers on current determinant.
              spawn%sdata(spawn%bit_str_len+1:spawn%bit_str_len+spawn%ntypes, idet) = pop
  
          end do
  
  
negative.code:         use dSFMT_interface, only: dSFMT_t
          use excitations, only: excit_t
          use system, only: sys_t
          use qmc_common, only: decide_nattempts
  
          type(sys_t), intent(in) :: sys
          type(spawn_t), intent(inout) :: spawn
  