From 13abddef2d95041d2f33a34d1318a5a6670d55bb Mon Sep 17 00:00:00 2001
From: Anthony Scemama <scemama@irsamc.ups-tlse.fr>
Date: Mon, 31 Aug 2020 23:04:34 +0200
Subject: [PATCH] Orthogonalized PT2

---
 src/cipsi/energy.irp.f                |  8 ++++++++
 src/cipsi/pt2_stoch_routines.irp.f    |  6 ++++++
 src/cipsi/selection.irp.f             | 10 +++++-----
 src/cipsi/zmq_selection.irp.f         |  2 ++
 src/scf_utils/roothaan_hall_scf.irp.f |  2 +-
 5 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/cipsi/energy.irp.f b/src/cipsi/energy.irp.f
index 37b29593..1d8c6bf5 100644
--- a/src/cipsi/energy.irp.f
+++ b/src/cipsi/energy.irp.f
@@ -37,3 +37,11 @@ BEGIN_PROVIDER [ double precision, pt2_E0_denominator, (N_states) ]
 END_PROVIDER
 
 
+BEGIN_PROVIDER [ double precision, pt2_overlap, (N_states, N_states) ]
+ implicit none
+ BEGIN_DOC
+ ! Overlap between the perturbed wave functions
+ END_DOC
+ pt2_overlap(1:N_states,1:N_states) = 0.d0
+END_PROVIDER
+
diff --git a/src/cipsi/pt2_stoch_routines.irp.f b/src/cipsi/pt2_stoch_routines.irp.f
index a10cfebd..f268430f 100644
--- a/src/cipsi/pt2_stoch_routines.irp.f
+++ b/src/cipsi/pt2_stoch_routines.irp.f
@@ -314,6 +314,12 @@ subroutine ZMQ_pt2(E, pt2_data, pt2_data_err, relative_error, N_in)
 
       print '(A)', '========== ================= =========== =============== =============== ================='
 
+    pt2_overlap(:,pt2_stoch_istate) = pt2_data % overlap(:,pt2_stoch_istate)
+print *, 'Overlap'
+print *, pt2_overlap(:,pt2_stoch_istate)
+print *, '-------'
+    SOFT_TOUCH pt2_overlap
+
     enddo
     FREE pt2_stoch_istate
 
diff --git a/src/cipsi/selection.irp.f b/src/cipsi/selection.irp.f
index e315a852..6813b5a1 100644
--- a/src/cipsi/selection.irp.f
+++ b/src/cipsi/selection.irp.f
@@ -787,11 +787,11 @@ subroutine fill_buffer_double(i_generator, sp, h1, h2, bannedOrb, banned, fock_d
       enddo
 
       ! Gram-Schmidt using input overlap matrix
-!      do istate=1,N_states
-!        do jstate=1,istate-1
-!          coef(istate) = coef(istate) - pt2_overlap(jstate,istate)/(pt2_overlap(jstate,jstate)) * coef(jstate)
-!        enddo
-!      enddo
+      do istate=1,N_states
+        do jstate=1,istate-1
+          coef(istate) = coef(istate) - pt2_overlap(istate,jstate)/(1.d0+pt2_overlap(jstate,jstate)) * coef(jstate)
+        enddo
+      enddo
 
       do istate=1,N_states
         alpha_h_psi = mat(istate, p1, p2)
diff --git a/src/cipsi/zmq_selection.irp.f b/src/cipsi/zmq_selection.irp.f
index e94fd422..9ce345cf 100644
--- a/src/cipsi/zmq_selection.irp.f
+++ b/src/cipsi/zmq_selection.irp.f
@@ -140,6 +140,8 @@ subroutine ZMQ_selection(N_in, pt2_data)
        pt2_data % pt2(k)/(1.d0 + pt2_data % overlap(k,k))
   enddo
 
+  pt2_overlap(:,:) = pt2_data % overlap(:,:)
+  SOFT_TOUCH pt2_overlap
   call update_pt2_and_variance_weights(pt2_data, N_states)
 
 end subroutine
diff --git a/src/scf_utils/roothaan_hall_scf.irp.f b/src/scf_utils/roothaan_hall_scf.irp.f
index 17458d9a..2b231c2b 100644
--- a/src/scf_utils/roothaan_hall_scf.irp.f
+++ b/src/scf_utils/roothaan_hall_scf.irp.f
@@ -186,10 +186,10 @@ END_DOC
 
   implicit none
 
+  integer,intent(inout)         :: dim_DIIS
   double precision,intent(in)   :: Fock_matrix_DIIS(ao_num,ao_num,dim_DIIS),error_matrix_DIIS(ao_num,ao_num,dim_DIIS)
   integer,intent(in)            :: iteration_SCF, size_Fock_matrix_AO
   double precision,intent(inout):: Fock_matrix_AO_(size_Fock_matrix_AO,ao_num)
-  integer,intent(inout)         :: dim_DIIS
 
   double precision,allocatable  :: B_matrix_DIIS(:,:),X_vector_DIIS(:)
   double precision,allocatable  :: C_vector_DIIS(:)