quantum_package/src/CISD/cisd_sc2.irp.f

program cisd
  implicit none
  integer :: i,k
  double precision, allocatable  :: eigvalues(:),eigvectors(:,:)
  PROVIDE ref_bitmask_energy H_apply_buffer_allocated mo_bielec_integrals_in_map

  double precision :: pt2(10), norm_pert(10), H_pert_diag
  double precision,allocatable :: H_jj(:)
  double precision :: diag_h_mat_elem
  integer,allocatable :: iorder(:)

! N_states = 3
! touch N_states
  call H_apply_cisd
  allocate(eigvalues(n_states),eigvectors(n_det,n_states))
  print *,  'N_det = ', N_det
  print *,  'N_states = ', N_states
  psi_coef = - 1.d-4
  allocate(H_jj(n_det),iorder(n_det))
  do i = 1, N_det
   H_jj(i) = diag_h_mat_elem(psi_det(1,1,i),N_int)
   iorder(i) = i
  enddo
  call dsort(H_jj,iorder,n_det)

  do k=1,N_states
    psi_coef(iorder(k),k) = 1.d0
  enddo
  call davidson_diag(psi_det,psi_coef,eigvalues,size(psi_coef,1),N_det,N_states,N_int,output_CISD)
  do i = 1, N_states
   print*,'eigvalues(i) = ',eigvalues(i)
  enddo

  print *,  '---'
  print *,  'HF:', HF_energy
  print *,  '---'
  do i = 1,1
   print *,  'energy(i)     = ',eigvalues(i) + nuclear_repulsion
   print *,  'E_corr        = ',eigvalues(i) - ref_bitmask_energy
  enddo
  call CISD_SC2(psi_det,psi_coef,eigvalues,size(psi_coef,1),N_det,N_states,N_int,output_CISD)
  do i = 1, N_states
   print*,'eigvalues(i) = ',eigvalues(i)
  enddo
  deallocate(eigvalues,eigvectors)
end