diff --git a/src/csf/configurations.irp.f b/src/csf/configurations.irp.f
index 8e2a513c..336691c2 100644
--- a/src/csf/configurations.irp.f
+++ b/src/csf/configurations.irp.f
@@ -748,34 +748,66 @@ subroutine binary_search_cfg(cfgInp,addcfg)
   implicit none
   BEGIN_DOC
   ! Documentation for binary_search
-  ! 
-  ! Does a binary search to find 
+  !
+  ! Does a binary search to find
   ! the address of a configuration in a list of
   ! configurations.
   END_DOC
   integer(bit_kind), intent(in)  :: cfgInp(N_int,2)
   integer          , intent(out) :: addcfg
-  integer :: i,j,k,r,l
-  integer*8 :: key, key2
-  logical :: found
-  !integer*8, allocatable :: bit_tmp(:)
-  !integer*8, external            :: configuration_search_key
 
-  !allocate(bit_tmp(0:N_configuration))
-  !bit_tmp(0) = 0
-  do i=1,N_configuration
-    !bit_tmp(i) = configuration_search_key(psi_configuration(1,1,i),N_int)
-    found = .True.
-    do k=1,N_int
-      found = found .and. (psi_configuration(k,1,i) == cfgInp(k,1)) &
-                    .and. (psi_configuration(k,2,i) == cfgInp(k,2))
-    enddo
-    if (found) then
-      addcfg = i
-      exit
+  logical                        :: found
+  integer                        :: l, r, j, k
+  integer*8                      :: bit_tmp, key
+
+  integer*8, external            :: configuration_search_key
+
+  key = configuration_search_key(cfgInp,N_int)
+
+  ! Binary search
+  l = 0
+  r = N_configuration+1
+  j = shiftr(r-l,1)
+  do while (j>=1)
+    j = j+l
+    bit_tmp = configuration_search_key(psi_configuration(1,1,j),N_int)
+    if (bit_tmp == key) then
+      ! Find 1st element which matches the key
+      if (j > 1) then
+        bit_tmp = configuration_search_key(psi_configuration(1,1,j-1),N_int)
+        do while (j>1 .and. bit_tmp == key)
+          j = j-1
+          bit_tmp = configuration_search_key(psi_configuration(1,1,j-1),N_int)
+        enddo
+        bit_tmp = key
+      endif
+      ! Find correct element matching the key
+      do while (bit_tmp == key)
+        found = .True.
+        do k=1,N_int
+          found = found .and. (psi_configuration(k,1,j) == cfgInp(k,1))&
+                        .and. (psi_configuration(k,2,j) == cfgInp(k,2))
+        enddo
+        if (found) then
+          addcfg = j
+          return
+        endif
+        j = j+1
+        bit_tmp = configuration_search_key(psi_configuration(1,1,j),N_int)
+      enddo
+      addcfg = -1
+      return
+    else if (bit_tmp > key) then
+      r = j
+    else
+      l = j
     endif
+    j = shiftr(r-l,1)
   enddo
 
+  addcfg = -1
+  return
+
 end subroutine
 
  BEGIN_PROVIDER [ integer, psi_configuration_to_psi_det, (2,N_configuration) ]
@@ -812,7 +844,7 @@ end subroutine
  psi_configuration_to_psi_det(2,k) = N_det
 
 
- ! Reorder determinants according to generation 
+ ! Reorder determinants according to generation
  ! --------------------------------------------
 
  integer(bit_kind), allocatable :: dets(:,:,:)
diff --git a/src/davidson/diagonalization_hcsf_dressed.irp.f b/src/davidson/diagonalization_hcsf_dressed.irp.f
index 429b5f98..ca63874a 100644
--- a/src/davidson/diagonalization_hcsf_dressed.irp.f
+++ b/src/davidson/diagonalization_hcsf_dressed.irp.f
@@ -306,23 +306,23 @@ subroutine davidson_diag_csf_hjj(dets_in,u_in,H_jj,energies,dim_in,sze,sze_csf,N
         PROVIDE mo_two_e_integrals_in_map mo_integrals_map big_array_exchange_integrals
         if ((sze > 100000).and.distributed_davidson) then
 
-            !call convertWFfromCSFtoDET(N_st_diag,U_csf(1,shift+1),U)
-            !call convertWFfromCSFtoDET(N_st_diag,W_csf(1,shift+1),W)
-            !call H_u_0_nstates_zmq   (W,U,N_st_diag,sze)
-            !call convertWFfromDETtoCSF(N_st_diag,U,U_csf(1,shift+1))
-            !call convertWFfromDETtoCSF(N_st_diag,W,W_csf(1,shift+1))
-            !call calculate_sigma_vector_cfg_nst(W_csf(1,shift+1),U_csf(1,shift+1),N_st_diag,sze_csf,1,sze_csf,0,1)
-            ! TODO : psi_det_size ? for psi_det
+!             call convertWFfromCSFtoDET(N_st_diag,U_csf(1,shift+1),U)
+!             call convertWFfromCSFtoDET(N_st_diag,W_csf(1,shift+1),W)
+!             call H_u_0_nstates_zmq   (W,U,N_st_diag,sze)
+!             call convertWFfromDETtoCSF(N_st_diag,U,U_csf(1,shift+1))
+!             call convertWFfromDETtoCSF(N_st_diag,W,W_csf(1,shift+1))
+!             call calculate_sigma_vector_cfg_nst(W_csf(1,shift+1),U_csf(1,shift+1),N_st_diag,sze_csf,1,sze_csf,0,1)
+!            ! TODO : psi_det_size ? for psi_det
             do kk=1,N_st_diag
                 call calculate_sigma_vector_cfg_nst(W_csf(1,shift+kk),U_csf(1,shift+kk),1,sze_csf,1,sze_csf,0,1)
             enddo
         else
-            !call convertWFfromCSFtoDET(N_st_diag,U_csf(1,shift+1),U)
-            !call convertWFfromCSFtoDET(N_st_diag,W_csf(1,shift+1),W)
-            !call H_u_0_nstates_openmp(W,U,N_st_diag,sze)
-            !call convertWFfromDETtoCSF(N_st_diag,U,U_csf(1,shift+1))
-            !call convertWFfromDETtoCSF(N_st_diag,W,W_csf(1,shift+1))
-            !call calculate_sigma_vector_cfg_nst(W_csf(1,shift+1),U_csf(1,shift+1),N_st_diag,sze_csf,1,sze_csf,0,1)
+!             call convertWFfromCSFtoDET(N_st_diag,U_csf(1,shift+1),U)
+!             call convertWFfromCSFtoDET(N_st_diag,W_csf(1,shift+1),W)
+!             call H_u_0_nstates_openmp(W,U,N_st_diag,sze)
+!             call convertWFfromDETtoCSF(N_st_diag,U,U_csf(1,shift+1))
+!             call convertWFfromDETtoCSF(N_st_diag,W,W_csf(1,shift+1))
+!             call calculate_sigma_vector_cfg_nst(W_csf(1,shift+1),U_csf(1,shift+1),N_st_diag,sze_csf,1,sze_csf,0,1)
             do kk=1,N_st_diag
                 call calculate_sigma_vector_cfg_nst(W_csf(1,shift+kk),U_csf(1,shift+kk),1,sze_csf,1,sze_csf,0,1)
             enddo