anchor.diff:                      call simple_update_proj_energy(ref_det == idet, H0i, psip_list%pops(1,idet), qs, qs%estimators%proj_energy)
   
                       ! Attempt to spawn from each particle onto all connected determinants.
  -                    if (sparse_hamil) then
  +                    if (sparse_hamil .and. allocated(hamil_csr%mat)) then
                           associate(hstart=>hamil_csr%row_ptr(idet), hend=>hamil_csr%row_ptr(idet+1)-1)
                               do ipart = 1, abs(psip_list%pops(1,idet))
                                   call attempt_spawn(rng, spawn, qs%tau, idet, &
  
positive.code:         !    pop: main population on each site before (input) and after (output)
          !         annihilation.
   
          type(spawn_t), intent(in)  :: spawn
          integer(int_p), intent(inout) :: pop(:,:)
  
  
negative.code: use const
  use dSFMT_interface
  use errors
  
  implicit none
  
  