From e3114aa5665fd571c06829780b0e8e178012f7a0 Mon Sep 17 00:00:00 2001
From: Anthony Scemama <scemama@irsamc.ups-tlse.fr>
Date: Wed, 28 Sep 2016 21:14:35 +0200
Subject: [PATCH] Added dummy selection

---
 plugins/Full_CI/H_apply.irp.f            |  5 ++++
 plugins/Perturbation/pt2_equations.irp.f | 31 ++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/plugins/Full_CI/H_apply.irp.f b/plugins/Full_CI/H_apply.irp.f
index 9e22b965..d870e4b0 100644
--- a/plugins/Full_CI/H_apply.irp.f
+++ b/plugins/Full_CI/H_apply.irp.f
@@ -23,6 +23,11 @@ s.unset_skip()
 #s.unset_openmp()
 print s
 
+s = H_apply("FCI_no_selection")
+s.set_selection_pt2("dummy")
+s.unset_skip()
+print s
+
 s = H_apply("FCI_mono")
 s.set_selection_pt2("epstein_nesbet_2x2")
 s.unset_double_excitations()
diff --git a/plugins/Perturbation/pt2_equations.irp.f b/plugins/Perturbation/pt2_equations.irp.f
index e406cd03..66083f6f 100644
--- a/plugins/Perturbation/pt2_equations.irp.f
+++ b/plugins/Perturbation/pt2_equations.irp.f
@@ -345,6 +345,37 @@ subroutine pt2_epstein_nesbet_sc2 ($arguments)
   
 end
 
+subroutine pt2_dummy ($arguments)
+  use bitmasks
+  implicit none
+  $declarations
+  
+  BEGIN_DOC
+  ! Dummy perturbation to add all connected determinants.
+  END_DOC
+  
+  integer                        :: i,j
+  double precision               :: diag_H_mat_elem_fock, h
+  double precision               :: i_H_psi_array(N_st)
+  PROVIDE  selection_criterion
+
+  call i_H_psi_minilist(det_pert,minilist,idx_minilist,N_minilist,psi_selectors_coef,Nint,N_minilist,psi_selectors_size,N_st,i_H_psi_array)
+  
+  h = diag_H_mat_elem_fock(det_ref,det_pert,fock_diag_tmp,Nint)
+  do i =1,N_st
+    if (i_H_psi_array(i) /= 0.d0) then
+     c_pert(i) = i_H_psi_array(i) / (electronic_energy(i) - h)
+     H_pert_diag(i) = h*c_pert(i)*c_pert(i)
+     e_2_pert(i) = 1.d0
+    else
+      c_pert(i) = 0.d0
+      e_2_pert(i) = 0.d0
+      H_pert_diag(i) = 0.d0
+    endif
+  enddo
+  
+end
+
 
 
 SUBST [ arguments, declarations ]