* Update the CI state average energy

Computes the state average energy 
\begin{align*}
E =\sum_{i=1}^{N_{states}} E_i . w_i
\end{align*}

$E_i$: energy of state i
$w_i$: weight of state i

#+BEGIN_SRC f90 :comments org :tangle update_st_av_ci_energy.irp.f
subroutine update_st_av_ci_energy(energy)

  implicit none
  
  double precision, intent(out) :: energy
  integer :: i

  energy = 0d0
  do i = 1, N_states
    energy = energy + ci_energy(i) * state_average_weight(i)
  enddo
  
  print*, 'ci_energy :', energy
end
#+END_SRC