diff --git a/Doc/release-notes b/Doc/release-notes
index f87fc725c..07689e8aa 100644
--- a/Doc/release-notes
+++ b/Doc/release-notes
@@ -8,7 +8,7 @@ New in development version:
     Localized exchange can deal with virtual orbitals (empty bands)
     (Ivan Carnimeo)
 
-  * Spin-polarized B3LYP (experimental)
+  * Spin-polarized X3LYP (experimental)
 
 Problems fixed in development version:
 
diff --git a/GWW/pw4gww/make.depend b/GWW/pw4gww/make.depend
index 5dafe82c3..e9e26e640 100644
--- a/GWW/pw4gww/make.depend
+++ b/GWW/pw4gww/make.depend
@@ -275,6 +275,7 @@ produce_wannier_gamma.o : ../../Modules/wannier_gw.o
 produce_wannier_gamma.o : ../../Modules/wavefunctions.o
 produce_wannier_gamma.o : ../../PW/src/extfield.o
 produce_wannier_gamma.o : ../../PW/src/exx.o
+produce_wannier_gamma.o : ../../PW/src/exx_base.o
 produce_wannier_gamma.o : ../../PW/src/ldaU.o
 produce_wannier_gamma.o : ../../PW/src/pwcom.o
 produce_wannier_gamma.o : ../../PW/src/scf_mod.o
@@ -385,7 +386,7 @@ v_basis.o : ../../Modules/kind.o
 v_basis.o : ../../Modules/mp_world.o
 v_basis.o : ../../Modules/recvec.o
 v_basis.o : ../../Modules/wannier_gw.o
-v_basis.o : ../../PW/src/exx.o
+v_basis.o : ../../PW/src/exx_base.o
 v_basis.o : ../../PW/src/pwcom.o
 v_basis.o : ../../UtilXlib/mp.o
 wannier.o : ../../Modules/cell_base.o
diff --git a/Makefile b/Makefile
index cb08661c5..3317c799e 100644
--- a/Makefile
+++ b/Makefile
@@ -378,10 +378,6 @@ doc_clean :
 	( if test -f $$dir/Makefile ; then \
 	( cd $$dir; $(MAKE) TLDEPS= clean ) ; fi ) ;  done
 
-depend: libiotk version
+depend: libiotk
 	@echo 'Checking dependencies...'
 	- ( if test -x install/makedeps.sh ; then install/makedeps.sh ; fi)
-# update file containing version number before looking for dependencies
-
-version:
-	- ( cd Modules; make version )
diff --git a/PP/src/make.depend b/PP/src/make.depend
index 7024ae6f7..234f2d8b8 100644
--- a/PP/src/make.depend
+++ b/PP/src/make.depend
@@ -380,6 +380,7 @@ open_grid.o : ../../Modules/recvec.o
 open_grid.o : ../../Modules/wavefunctions.o
 open_grid.o : ../../PW/src/buffers.o
 open_grid.o : ../../PW/src/exx.o
+open_grid.o : ../../PW/src/exx_base.o
 open_grid.o : ../../PW/src/io_rho_xml.o
 open_grid.o : ../../PW/src/pwcom.o
 open_grid.o : ../../PW/src/scf_mod.o
diff --git a/PW/src/Makefile b/PW/src/Makefile
index e9aeee9d0..c73b169d0 100644
--- a/PW/src/Makefile
+++ b/PW/src/Makefile
@@ -73,6 +73,7 @@ ewald.o \
 ewald_dipole.o \
 extfield.o \
 exx_base.o \
+exx_band.o \
 exx.o \
 fcp.o \
 find_group.o \
diff --git a/PW/src/exx.f90 b/PW/src/exx.f90
index 4cceb1f59..49e54ce63 100644
--- a/PW/src/exx.f90
+++ b/PW/src/exx.f90
@@ -1,4 +1,4 @@
-! Copyright (C) 2005-2015 Quantum ESPRESSO group
+! Copyrigh(C) 2005-2018 Quantum ESPRESSO group
 ! This file is distributed under the terms of the
 ! GNU General Public License. See the file `License'
 ! in the root directory of the present distribution,
@@ -15,44 +15,40 @@ MODULE exx
   ! Computer Physics Communications 2017, dx.doi.org/10.1016/j.cpc.2017.01.008
   !
   USE kinds,                ONLY : DP
-  USE coulomb_vcut_module,  ONLY : vcut_init, vcut_type, vcut_info, &
-                                   vcut_get,  vcut_spheric_get
   USE noncollin_module,     ONLY : noncolin, npol
-  USE io_global,            ONLY : ionode
+  USE io_global,            ONLY : ionode, stdout
   !
   USE control_flags,        ONLY : gamma_only, tqr
   USE fft_types,            ONLY : fft_type_descriptor
   USE stick_base,           ONLY : sticks_map, sticks_map_deallocate
   !
-  USE io_global,            ONLY : stdout
-
   IMPLICIT NONE
   SAVE
-  COMPLEX(DP), ALLOCATABLE :: psi_exx(:,:), hpsi_exx(:,:)
-  COMPLEX(DP), ALLOCATABLE :: evc_exx(:,:), psic_exx(:)
-  INTEGER :: lda_original, n_original
-  integer :: ibnd_buff_start, ibnd_buff_end
   !
   ! general purpose vars
   !
-  REAL(DP):: exxalfa=0._dp                ! 1 if exx, 0 elsewhere
-  !
+  ! exxalfa is the parameter multiplying the exact-exchange part
+  REAL(DP):: exxalfa=0._dp
+  ! x_occupation(nbnd,nkstot) the weight of
+  ! auxiliary functions in the density matrix
   REAL(DP),    ALLOCATABLE :: x_occupation(:,:)
-                                         ! x_occupation(nbnd,nkstot) the weight of
-                                         ! auxiliary functions in the density matrix
-
-  INTEGER :: x_nbnd_occ                  ! number of bands of auxiliary functions with
-                                         ! at least some x_occupation > eps_occ
+  ! number of bands of auxiliary functions with
+  ! at least some x_occupation > eps_occ
+  INTEGER :: x_nbnd_occ
   REAL(DP), PARAMETER :: eps_occ  = 1.d-8
-  INTEGER :: ibnd_start = 0              ! starting band index used in bgrp parallelization
-  INTEGER :: ibnd_end = 0                ! ending band index used in bgrp parallelization
-
+  ! 
+  ! Buffers: temporary (complex) buffer for wfc storage
   COMPLEX(DP), ALLOCATABLE :: exxbuff(:,:,:)
-                                         ! temporary (complex) buffer for wfc storage
+  ! temporary (real) buffer for wfc storage
   REAL(DP), ALLOCATABLE    :: locbuff(:,:,:)
-                                         ! temporary (real) buffer for wfc storage
+  ! buffer for matrix of localization integrals
   REAL(DP), ALLOCATABLE    :: locmat(:,:,:)
-                                         ! buffer for matrix of localization integrals
+  !
+#if defined(__USE_INTEL_HBM_DIRECTIVES)
+!DIR$ ATTRIBUTES FASTMEM :: exxbuff
+#elif defined(__USE_CRAY_HBM_DIRECTIVES)
+!DIR$ memory(bandwidth) exxbuff
+#endif
   !
   LOGICAL :: use_ace        !  true: Use Lin Lin's ACE method
                             !  false: do not use ACE, use old algorithm instead
@@ -64,14 +60,6 @@ MODULE exx
                                ! discard contribution to V_x if overlap between
                                ! localized orbitals is smaller than "local_thr"
   !
-  !
-#if defined(__USE_INTEL_HBM_DIRECTIVES)
-!DIR$ ATTRIBUTES FASTMEM :: exxbuff
-#elif defined(__USE_CRAY_HBM_DIRECTIVES)
-!DIR$ memory(bandwidth) exxbuff
-#endif
-  !
-  !
   ! energy related variables
   !
   REAL(DP) :: fock0 = 0.0_DP, & !   sum <old|Vx(old)|old>
@@ -97,57 +85,11 @@ MODULE exx
   ! energy cutoff for custom grid
   REAL(DP)  :: ecutfock
   !
-  ! mapping for the data structure conversion
+  ! starting and ending band index used in bgrp parallelization
+  INTEGER :: ibnd_start = 0, ibnd_end = 0
+  ! starting and ending buffer index used in bgrp parallelization
+  integer :: ibnd_buff_start, ibnd_buff_end
   !
-  TYPE comm_packet
-     INTEGER :: size
-     INTEGER, ALLOCATABLE :: indices(:)
-     COMPLEX(DP), ALLOCATABLE :: msg(:,:,:)
-  END TYPE comm_packet
-  TYPE(comm_packet), ALLOCATABLE :: comm_recv(:,:), comm_send(:,:)
-  TYPE(comm_packet), ALLOCATABLE :: comm_recv_reverse(:,:)
-  TYPE(comm_packet), ALLOCATABLE :: comm_send_reverse(:,:,:)
-  INTEGER, ALLOCATABLE :: lda_local(:,:)
-  INTEGER, ALLOCATABLE :: lda_exx(:,:)
-  INTEGER, ALLOCATABLE :: ngk_local(:), ngk_exx(:)
-  INTEGER, ALLOCATABLE :: igk_exx(:,:)
-  INTEGER :: npwx_local = 0
-  INTEGER :: npwx_exx = 0
-  INTEGER :: npw_local = 0
-  INTEGER :: npw_exx = 0
-  INTEGER :: n_local = 0
-  INTEGER :: nwordwfc_exx
-  LOGICAL :: first_data_structure_change = .TRUE.
-
-  INTEGER :: ngm_loc, ngm_g_loc, gstart_loc
-  INTEGER, ALLOCATABLE :: ig_l2g_loc(:)
-  REAL(DP), ALLOCATABLE :: g_loc(:,:), gg_loc(:)
-  INTEGER, ALLOCATABLE :: mill_loc(:,:), nl_loc(:)
-  INTEGER :: ngms_loc, ngms_g_loc
-  INTEGER, ALLOCATABLE :: nls_loc(:)
-  INTEGER, ALLOCATABLE :: nlm_loc(:)
-  INTEGER, ALLOCATABLE :: nlsm_loc(:)
-
-  !gcutm
-  INTEGER :: ngm_exx, ngm_g_exx, gstart_exx
-  INTEGER, ALLOCATABLE :: ig_l2g_exx(:)
-  REAL(DP), ALLOCATABLE :: g_exx(:,:), gg_exx(:)
-  INTEGER, ALLOCATABLE :: mill_exx(:,:), nl_exx(:)
-  INTEGER :: ngms_exx, ngms_g_exx
-  INTEGER, ALLOCATABLE :: nls_exx(:)
-  INTEGER, ALLOCATABLE :: nlm_exx(:)
-  INTEGER, ALLOCATABLE :: nlsm_exx(:)
-  !gcutms
-
-  !list of which coulomb factors have been calculated already
-  LOGICAL, ALLOCATABLE :: coulomb_done(:,:)
-
-  TYPE(fft_type_descriptor) :: dfftp_loc, dffts_loc
-  TYPE(fft_type_descriptor) :: dfftp_exx, dffts_exx
-  TYPE (sticks_map) :: smap_exx ! Stick map descriptor
-  INTEGER :: ngw_loc, ngs_loc
-  INTEGER :: ngw_exx, ngs_exx
-
  CONTAINS
 #define _CX(A)  CMPLX(A,0._dp,kind=DP)
 #define _CY(A)  CMPLX(0._dp,-A,kind=DP)
@@ -170,6 +112,7 @@ MODULE exx
     !
     USE control_flags,ONLY : tqr
     USE realus,       ONLY : qpointlist, tabxx, tabp
+    USE exx_band,     ONLY : smap_exx
 
     IMPLICIT NONE
     INTEGER :: ik, ngmt
@@ -342,7 +285,7 @@ MODULE exx
     ! DoLoc = .true.  ...    Real Array locbuff(ir, nbnd, nkqs)
     !         .false. ... Complex Array exxbuff(ir, nbnd/2, nkqs)
     !
-    USE wavefunctions_module, ONLY : evc, psic
+    USE wavefunctions_module, ONLY : evc
     USE io_files,             ONLY : nwordwfc, iunwfc_exx
     USE buffers,              ONLY : get_buffer
     USE wvfct,                ONLY : nbnd, npwx, wg, current_k
@@ -366,6 +309,8 @@ MODULE exx
     USE exx_base,             ONLY : nkqs, xkq_collect, index_xk, index_sym, &
          exx_set_symm, rir, working_pool, exxdiv, erfc_scrlen, gau_scrlen, &
          exx_divergence
+    USE exx_band,             ONLY : change_data_structure, nwordwfc_exx, &
+         transform_evc_to_exx, igk_exx, evc_exx
     !
     IMPLICIT NONE
     INTEGER :: ik,ibnd, i, j, k, ir, isym, ikq, ig
@@ -380,6 +325,7 @@ MODULE exx
 !DIR$ memory(bandwidth) temppsic
 #endif
     COMPLEX(DP),ALLOCATABLE :: temppsic_nc(:,:), psic_nc(:,:)
+    COMPLEX(DP),ALLOCATABLE :: psic_exx(:)
     INTEGER :: nxxs, nrxxs
 #if defined(__MPI)
     COMPLEX(DP),ALLOCATABLE  :: temppsic_all(:),      psic_all(:)
@@ -417,11 +363,6 @@ MODULE exx
     ! Note that nxxs is not the same as nrxxs in parallel case
     nxxs = dfftt%nr1x *dfftt%nr2x *dfftt%nr3x
     nrxxs= dfftt%nnr
-    !allocate psic_exx
-    IF(.not.allocated(psic_exx))THEN
-       ALLOCATE(psic_exx(nrxxs))
-       psic_exx = 0.0_DP
-    END IF
 #if defined(__MPI)
     IF (noncolin) THEN
        ALLOCATE(psic_all_nc(nxxs,npol), temppsic_all_nc(nxxs,npol) )
@@ -434,6 +375,7 @@ MODULE exx
     ELSEIF ( .not. gamma_only ) THEN
        ALLOCATE(temppsic(nrxxs))
     ENDIF
+    ALLOCATE(psic_exx(nrxxs))
     !
     IF (.not.exx_is_active()) THEN
        !
@@ -528,7 +470,6 @@ MODULE exx
          ENDDO
       ENDDO
     END IF
-
     !
     !   This is parallelized over pools. Each pool computes only its k-points
     !
@@ -744,6 +685,7 @@ MODULE exx
     ENDDO&
     KPOINTS_LOOP
     !
+    DEALLOCATE (psic_exx)
     IF (noncolin) THEN
        DEALLOCATE(temppsic_nc, psic_nc)
 #if defined(__MPI)
@@ -809,6 +751,8 @@ MODULE exx
     USE us_exx,         ONLY : becxx
     USE mp_exx,         ONLY : negrp, inter_egrp_comm, init_index_over_band
     USE wvfct,          ONLY : nbnd
+    USE exx_band,       ONLY : transform_psi_to_exx, transform_hpsi_to_local,&
+                               psi_exx, hpsi_exx, igk_exx
     !
     IMPLICIT NONE
     !
@@ -886,6 +830,7 @@ MODULE exx
     USE paw_exx,        ONLY : PAW_newdxx
     USE exx_base,       ONLY : nqs, index_xkq, index_xk, xkq_collect, &
          coulomb_fac, g2_convolution_all
+    USE exx_band,       ONLY : exxbuff_comm_gamma, result_sum, igk_exx
     !
     !
     IMPLICIT NONE
@@ -909,7 +854,6 @@ MODULE exx
     INTEGER          :: h_ibnd, nrxxs
     REAL(DP) :: x1, x2, xkp(3)
     REAL(DP) :: xkq(3)
-    ! <LMS> temp array for vcut_spheric
     INTEGER, EXTERNAL :: global_kpoint_index
     LOGICAL :: l_fft_doubleband
     LOGICAL :: l_fft_singleband
@@ -973,7 +917,8 @@ MODULE exx
           index_end = min(index_start+jblock-1,nbnd/2)
           !
           !gather exxbuff for jblock_start:jblock_end
-          call exxbuff_comm_gamma(exxtemp,current_k,nrxxs*npol,jblock_start,jblock_end,jblock)
+          call exxbuff_comm_gamma( exxbuff, exxtemp, current_k,nrxxs*npol,&
+                  jblock_start,jblock_end,jblock)
           !
           LOOP_ON_PSI_BANDS : &
           DO ii = 1,  nibands(my_egrp_id+1)
@@ -1246,6 +1191,7 @@ MODULE exx
     USE paw_exx,        ONLY : PAW_newdxx
     USE exx_base,       ONLY : nqs, xkq_collect, index_xkq, index_xk, &
          coulomb_fac, g2_convolution_all
+    USE exx_band,       ONLY : exxbuff_comm, result_sum, igk_exx
     USE io_global,      ONLY : stdout
     !
     !
@@ -1285,7 +1231,6 @@ MODULE exx
     INTEGER  :: h_ibnd, nrxxs
     REAL(DP) :: x1, x2, xkp(3), omega_inv, nqs_inv
     REAL(DP) :: xkq(3)
-    ! <LMS> temp array for vcut_spheric
     INTEGER, EXTERNAL :: global_kpoint_index
     DOUBLE PRECISION :: max, tempx
     COMPLEX(DP), ALLOCATABLE :: big_result(:,:)
@@ -1380,18 +1325,10 @@ MODULE exx
        !
     END DO
     !
-    !
-    !
-    !
-    !
-    !
-    !
     !precompute these guys
     omega_inv = 1.0 / omega
     nqs_inv = 1.0 / nqs
     !
-    !
-    !
     !------------------------------------------------------------------------!
     ! Beginning of main loop
     !------------------------------------------------------------------------!
@@ -1421,7 +1358,8 @@ MODULE exx
           jblock_end = min(jblock_start+jblock-1,nbnd)
           !
           !gather exxbuff for jblock_start:jblock_end
-          call exxbuff_comm(exxtemp,ikq,nrxxs*npol,jblock_start,jblock_end)
+          call exxbuff_comm( exxbuff, exxtemp, ikq, nrxxs*npol, &
+                  jblock_start,jblock_end)
           !
           DO ii=1, nibands(my_egrp_id+1)
              !
@@ -1711,6 +1649,7 @@ MODULE exx
     USE becmod,                 ONLY : bec_type, allocate_bec_type, &
                                        deallocate_bec_type, calbec
     USE uspp,                   ONLY : okvan,nkb,vkb
+    USE exx_band,               ONLY : nwordwfc_exx, igk_exx
 
     IMPLICIT NONE
 
@@ -1830,6 +1769,9 @@ MODULE exx
                                         addusxx_r, qvan_init, qvan_clean
     USE exx_base,                ONLY : nqs, xkq_collect, index_xkq, index_xk, &
          coulomb_fac, g2_convolution_all
+    USE exx_band,                ONLY : exxbuff_comm_gamma, igk_exx, &
+         change_data_structure, transform_evc_to_exx, nwordwfc_exx,  &
+         evc_exx
     !
     IMPLICIT NONE
     !
@@ -1845,7 +1787,6 @@ MODULE exx
     INTEGER  :: h_ibnd, nrxxs, current_ik, ibnd_loop_start
     REAL(DP) :: x1, x2
     REAL(DP) :: xkq(3), xkp(3), vc
-    ! temp array for vcut_spheric
     INTEGER, EXTERNAL :: global_kpoint_index
     !
     TYPE(bec_type) :: becpsi
@@ -1936,7 +1877,8 @@ MODULE exx
              index_end = min(index_start+jblock-1,nbnd/2)
              !
              !gather exxbuff for jblock_start:jblock_end
-             call exxbuff_comm_gamma(exxtemp,ikk,nrxxs*npol,jblock_start,jblock_end,jblock)
+             call exxbuff_comm_gamma( exxbuff, exxtemp, ikk, nrxxs*npol,&
+                     jblock_start,jblock_end,jblock)
              !
              JBND_LOOP : &
              DO ii = 1, nibands(my_egrp_id+1)
@@ -2158,6 +2100,8 @@ MODULE exx
                                         addusxx_r, qvan_init, qvan_clean
     USE exx_base,                ONLY : nqs, xkq_collect, index_xkq, index_xk, &
          coulomb_fac, g2_convolution_all
+    USE exx_band,                ONLY : exxbuff_comm, change_data_structure, &
+         transform_evc_to_exx, nwordwfc_exx, igk_exx, evc_exx
     !
     IMPLICIT NONE
     !
@@ -2176,7 +2120,6 @@ MODULE exx
     INTEGER  :: h_ibnd, nrxxs, current_ik, ibnd_loop_start, nblock, nrt, irt, ir_start, ir_end
     REAL(DP) :: x1, x2
     REAL(DP) :: xkq(3), xkp(3), vc, omega_inv
-    ! temp array for vcut_spheric
     INTEGER, EXTERNAL :: global_kpoint_index
     !
     TYPE(bec_type) :: becpsi
@@ -2290,7 +2233,8 @@ MODULE exx
              jblock_end = min(jblock_start+jblock-1,nbnd)
              !
              !gather exxbuff for jblock_start:jblock_end
-             call exxbuff_comm(exxtemp,ikq,nrxxs*npol,jblock_start,jblock_end)
+             call exxbuff_comm( exxbuff, exxtemp, ikq, nrxxs*npol, &
+                     jblock_start,jblock_end)
              !
              JBND_LOOP : &
              DO ii=1, nibands(my_egrp_id+1)
@@ -2469,10 +2413,14 @@ MODULE exx
     USE fft_interfaces,       ONLY : fwfft, invfft
     USE uspp,                 ONLY : okvan
     !
-    USE exx_base,            ONLY : nq1, nq2, nq3, nqs, eps, exxdiv, &
-         x_gamma_extrapolation, on_double_grid, grid_factor, yukawa, &
-         erfc_scrlen, use_coulomb_vcut_ws, use_coulomb_vcut_spheric, &
+    USE exx_base,             ONLY : nq1, nq2, nq3, nqs, eps, exxdiv, &
+         x_gamma_extrapolation, on_double_grid, grid_factor, yukawa,  &
+         erfc_scrlen, use_coulomb_vcut_ws, use_coulomb_vcut_spheric,  &
          gau_scrlen, vcut, index_xkq, index_xk, index_sym
+    USE exx_band,             ONLY : exxbuff_comm, exxbuff_comm_gamma, &
+         change_data_structure, transform_evc_to_exx, g_exx, igk_exx,  &
+         nwordwfc_exx, evc_exx
+    USE coulomb_vcut_module,  ONLY : vcut_get,  vcut_spheric_get
     !
     ! ---- local variables -------------------------------------------------
     !
@@ -2491,7 +2439,6 @@ MODULE exx
     INTEGER  :: ibnd_loop_start
     REAL(DP) :: x1, x2
     REAL(DP) :: qq, xk_cryst(3), sxk(3), xkq(3), vc(3,3), x, q(3)
-    ! temp array for vcut_spheric
     REAL(DP) :: delta(3,3)
     COMPLEX(DP), ALLOCATABLE :: exxtemp(:,:)
     INTEGER :: jstart, jend, ipair, jblock_start, jblock_end
@@ -2639,14 +2586,15 @@ MODULE exx
               jblock_start = (ijt - 1) * (2*jblock) + 1
               jblock_end = min(jblock_start+(2*jblock)-1,nbnd)
               !
-              call exxbuff_comm_gamma(exxtemp,ikq,nrxxs*npol,jblock_start,&
-                   jblock_end,jblock)
+              call exxbuff_comm_gamma(exxbuff, exxtemp, ikq, nrxxs*npol, &
+                      jblock_start, jblock_end, jblock)
            ELSE
               !
               jblock_start = (ijt - 1) * jblock + 1
               jblock_end = min(jblock_start+jblock-1,nbnd)
               !
-              call exxbuff_comm(exxtemp,ikq,nrxxs*npol,jblock_start,jblock_end)
+              call exxbuff_comm(exxbuff, exxtemp, ikq, nrxxs*npol, &
+                      jblock_start, jblock_end)
            END IF
            !
         DO ii = 1, nibands(my_egrp_id+1)
@@ -2971,1488 +2919,6 @@ SUBROUTINE compute_becpsi (npw_, igk_, q_, evc_exx, becpsi_k)
   return
 END SUBROUTINE compute_becpsi
   !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE transform_evc_to_exx(type)
-  !-----------------------------------------------------------------------
-    USE mp_exx,               ONLY : negrp
-    USE wvfct,                ONLY : npwx, nbnd
-    USE io_files,             ONLY : nwordwfc, iunwfc, iunwfc_exx
-    USE klist,                ONLY : nks, ngk, igk_k
-    USE uspp,                 ONLY : nkb, vkb
-    USE wavefunctions_module, ONLY : evc
-    USE control_flags,        ONLY : io_level
-    USE buffers,              ONLY : open_buffer, get_buffer, save_buffer
-    USE mp_exx,               ONLY : max_ibands
-    !
-    !
-    IMPLICIT NONE
-    !
-    INTEGER, intent(in) :: type
-    INTEGER :: lda, n, ik
-    LOGICAL :: exst_mem, exst_file
-    !
-    IF (negrp.eq.1) THEN
-       !
-       ! no change in data structure is necessary
-       ! just copy all of the required data
-       !
-       ! get evc_exx
-       !
-       IF(.not.allocated(evc_exx))THEN
-          ALLOCATE(evc_exx(npwx*npol,nbnd))
-       END IF
-       evc_exx = evc
-       !
-       ! get igk_exx
-       !
-       IF(.not.allocated(igk_exx)) THEN
-          ALLOCATE( igk_exx( npwx, nks ) )
-          igk_exx = igk_k
-       END IF
-       !
-       ! get the wfc buffer is used
-       !
-       iunwfc_exx = iunwfc
-       nwordwfc_exx = nwordwfc
-       !
-       RETURN
-       !
-    END IF
-    !
-    ! change the data structure of evc and igk
-    !
-    lda = npwx
-    n = npwx 
-    npwx_local = npwx
-    IF( .not.allocated(ngk_local) ) allocate(ngk_local(nks))
-    ngk_local = ngk
-    !
-    IF ( .not.allocated(comm_recv) ) THEN
-       !
-       ! initialize all of the conversion maps and change the data structure
-       !
-       CALL initialize_local_to_exact_map(lda, nbnd)
-    ELSE
-       !
-       ! change the data structure
-       !
-       CALL change_data_structure(.TRUE.)
-    END IF
-    !
-    lda = npwx
-    n = npwx 
-    npwx_exx = npwx
-    IF( .not.allocated(ngk_exx) ) allocate(ngk_exx(nks))
-    ngk_exx = ngk
-    !
-    ! get evc_exx
-    !
-    IF(.not.allocated(evc_exx))THEN
-       ALLOCATE(evc_exx(lda*npol,max_ibands+2))
-       !
-       ! ... open files/buffer for wavefunctions (nwordwfc set in openfil)
-       ! ... io_level > 1 : open file, otherwise: open buffer
-       !
-       nwordwfc_exx  = size(evc_exx)
-       CALL open_buffer( iunwfc_exx, 'wfc_exx', nwordwfc_exx, io_level, &
-            exst_mem, exst_file )
-    END IF
-    !
-    DO ik=1, nks
-       !
-       ! read evc for the local data structure
-       !
-       IF ( nks > 1 ) CALL get_buffer(evc, nwordwfc, iunwfc, ik)
-       !
-       ! transform evc to the EXX data structure
-       !
-       CALL transform_to_exx(lda, n, nbnd, nbnd, ik, evc, evc_exx, type)
-       !
-       ! save evc to a buffer
-       !
-       IF ( nks > 1 ) CALL save_buffer ( evc_exx, nwordwfc_exx, iunwfc_exx, ik )
-    END DO
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE transform_evc_to_exx
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE transform_psi_to_exx(lda, n, m, psi)
-  !-----------------------------------------------------------------------
-    USE wvfct,        ONLY : current_k, npwx, nbnd
-    USE mp_exx,       ONLY : negrp, nibands, my_egrp_id, max_ibands
-    !
-    !
-    IMPLICIT NONE
-    !
-    Integer, INTENT(in) :: lda
-    INTEGER, INTENT(in) :: m
-    INTEGER, INTENT(inout) :: n
-    COMPLEX(DP), INTENT(in) :: psi(lda*npol,m) 
-    !
-    ! change to the EXX data strucutre
-    !
-    npwx_local = npwx
-    n_local = n
-    IF ( .not.allocated(comm_recv) ) THEN
-       !
-       ! initialize all of the conversion maps and change the data structure
-       !
-       CALL initialize_local_to_exact_map(lda, m)
-    ELSE
-       !
-       ! change the data structure
-       !
-       CALL change_data_structure(.TRUE.)
-    END IF
-    npwx_exx = npwx
-    n = ngk_exx(current_k)
-    !
-    ! get igk
-    !
-    CALL update_igk(.TRUE.)
-    !
-    ! get psi_exx
-    !
-    CALL transform_to_exx(lda, n, m, max_ibands, &
-         current_k, psi, psi_exx, 0)
-    !
-    ! zero hpsi_exx
-    !
-    hpsi_exx = 0.d0
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE transform_psi_to_exx
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE transform_hpsi_to_local(lda, n, m, hpsi)
-  !-----------------------------------------------------------------------
-    USE mp_exx,         ONLY : iexx_istart, iexx_iend, my_egrp_id
-    !
-    IMPLICIT NONE
-    !
-    INTEGER, INTENT(in) :: lda
-    INTEGER, INTENT(in) :: m
-    INTEGER, INTENT(inout) :: n
-    COMPLEX(DP), INTENT(out) :: hpsi(lda_original*npol,m)
-    INTEGER :: m_exx
-    !
-    ! change to the local data structure
-    !
-    CALL change_data_structure(.FALSE.)
-    !
-    ! get igk
-    !
-    CALL update_igk(.FALSE.)
-    n = n_local
-    !
-    ! transform hpsi_exx to the local data structure
-    !
-    m_exx = iexx_iend(my_egrp_id+1) - iexx_istart(my_egrp_id+1) + 1
-    CALL transform_to_local(m,m_exx,hpsi_exx,hpsi)
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE transform_hpsi_to_local
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE initialize_local_to_exact_map(lda, m)
-  !-----------------------------------------------------------------------
-    !
-    ! determine the mapping between the local and EXX data structures
-    !
-    USE wvfct,          ONLY : npwx, nbnd
-    USE klist,          ONLY : nks, igk_k
-    USE mp_exx,         ONLY : nproc_egrp, negrp, my_egrp_id, me_egrp, &
-                               intra_egrp_comm, inter_egrp_comm, &
-                               ibands, nibands, init_index_over_band, &
-                               iexx_istart, iexx_iend, max_ibands
-    USE mp_pools,       ONLY : nproc_pool, me_pool, intra_pool_comm
-    USE mp,             ONLY : mp_sum
-    USE gvect,          ONLY : ig_l2g
-    USE uspp,           ONLY : nkb
-    !
-    !
-    IMPLICIT NONE
-    !
-    Integer :: lda
-    INTEGER :: n, m
-    INTEGER, ALLOCATABLE :: local_map(:,:), exx_map(:,:)
-    INTEGER, ALLOCATABLE :: l2e_map(:,:), e2l_map(:,:,:)
-    INTEGER, ALLOCATABLE :: psi_source(:), psi_source_exx(:,:)
-    INTEGER :: current_index
-    INTEGER :: i, j, k, ik, im, ig, count, iproc, prev, iegrp
-    INTEGER :: total_lda(nks), prev_lda(nks)
-    INTEGER :: total_lda_exx(nks), prev_lda_exx(nks)
-    INTEGER :: n_local
-    INTEGER :: lda_max_local, lda_max_exx
-    INTEGER :: max_lda_egrp
-    INTEGER :: request_send(nproc_egrp), request_recv(nproc_egrp)
-    INTEGER :: ierr
-    INTEGER :: egrp_base, total_lda_egrp(nks), prev_lda_egrp(nks)
-    INTEGER :: igk_loc(npwx)
-    !
-    ! initialize the pair assignments
-    !
-    CALL init_index_over_band(inter_egrp_comm,nbnd,m)
-    !
-    ! allocate bookeeping arrays
-    !
-    IF ( .not.allocated(comm_recv) ) THEN
-       ALLOCATE(comm_recv(nproc_egrp,nks),comm_send(nproc_egrp,nks))
-    END IF
-    IF ( .not.allocated(lda_local) ) THEN
-       ALLOCATE(lda_local(nproc_pool,nks))
-       ALLOCATE(lda_exx(nproc_egrp,nks))
-    END IF
-    !
-    ! store the original values of lda and n
-    !
-    lda_original = lda
-    n_original = n
-    !
-    ! construct the local map
-    !
-    lda_local = 0
-    DO ik = 1, nks
-       igk_loc = igk_k(:,ik)
-       n = 0
-       DO i = 1, size(igk_loc)
-          IF(igk_loc(i).gt.0)n = n + 1
-       END DO
-       lda_local(me_pool+1,ik) = n
-       CALL mp_sum(lda_local(:,ik),intra_pool_comm)
-       total_lda(ik) = sum(lda_local(:,ik))
-       prev_lda(ik) = sum(lda_local(1:me_pool,ik))
-    END DO
-    ALLOCATE(local_map(maxval(total_lda),nks))
-    local_map = 0
-    DO ik = 1, nks
-       local_map(prev_lda(ik)+1:prev_lda(ik)+lda_local(me_pool+1,ik),ik) = &
-            ig_l2g(igk_k(1:lda_local(me_pool+1,ik),ik))
-    END DO
-    CALL mp_sum(local_map,intra_pool_comm)
-    !
-    !-----------------------------------------!
-    ! Switch to the exx data structure        !
-    !-----------------------------------------!
-    !
-    CALL change_data_structure(.TRUE.)
-    !
-    ! construct the exx map
-    !
-    lda_exx = 0
-    DO ik = 1, nks
-       n = 0
-       DO i = 1, size(igk_exx(:,ik))
-          IF(igk_exx(i,ik).gt.0)n = n + 1
-       END DO
-       lda_exx(me_egrp+1,ik) = n
-       CALL mp_sum(lda_exx(:,ik),intra_egrp_comm)
-       total_lda_exx(ik) = sum(lda_exx(:,ik))
-       prev_lda_exx(ik) = sum(lda_exx(1:me_egrp,ik))
-    END DO
-    ALLOCATE(exx_map(maxval(total_lda_exx),nks))
-    exx_map = 0
-    DO ik = 1, nks
-       exx_map(prev_lda_exx(ik)+1:prev_lda_exx(ik)+lda_exx(me_egrp+1,ik),ik) = &
-            ig_l2g(igk_exx(1:lda_exx(me_egrp+1,ik),ik))    
-    END DO
-    CALL mp_sum(exx_map,intra_egrp_comm)
-    !
-    ! construct the l2e_map
-    !
-    allocate( l2e_map(maxval(total_lda_exx),nks) )
-    l2e_map = 0
-    DO ik = 1, nks
-       DO ig = 1, lda_exx(me_egrp+1,ik)
-          DO j=1, total_lda(ik)
-             IF( local_map(j,ik).EQ.exx_map(ig+prev_lda_exx(ik),ik) ) exit
-          END DO
-          l2e_map(ig+prev_lda_exx(ik),ik) = j
-       END DO
-    END DO
-    CALL mp_sum(l2e_map,intra_egrp_comm)
-    !
-    ! plan communication for the data structure change
-    !
-    lda_max_local = maxval(lda_local)
-    lda_max_exx = maxval(lda_exx)
-    allocate(psi_source(maxval(total_lda_exx)))
-    !
-    DO ik = 1, nks
-       !
-       ! determine which task each value will come from
-       !
-       psi_source = 0
-       DO ig = 1, lda_exx(me_egrp+1,ik)
-          j = 1
-          DO i = 1, nproc_pool
-             j = j + lda_local(i,ik)
-             IF( j.gt.l2e_map(ig+prev_lda_exx(ik),ik) ) exit
-          END DO
-          psi_source(ig+prev_lda_exx(ik)) = i-1
-       END DO
-       CALL mp_sum(psi_source,intra_egrp_comm)
-       !
-       ! allocate communication packets to receive psi and hpsi
-       !
-       DO iproc=0, nproc_egrp-1
-          !
-          ! determine how many values need to come from iproc
-          !
-          count = 0
-          DO ig=1, lda_exx(me_egrp+1,ik)
-             IF ( MODULO(psi_source(ig+prev_lda_exx(ik)),nproc_egrp)&
-                  .eq.iproc ) THEN
-                count = count + 1
-             END IF
-          END DO
-          !
-          ! allocate the communication packet
-          !
-          comm_recv(iproc+1,ik)%size = count
-          IF (count.gt.0) THEN
-             IF (.not.ALLOCATED(comm_recv(iproc+1,ik)%msg)) THEN
-                ALLOCATE(comm_recv(iproc+1,ik)%indices(count))
-                ALLOCATE(comm_recv(iproc+1,ik)%msg(count,npol,max_ibands+2))
-             END IF
-          END IF
-          !
-          ! determine which values need to come from iproc
-          !
-          count = 0
-          DO ig=1, lda_exx(me_egrp+1,ik)
-             IF ( MODULO(psi_source(ig+prev_lda_exx(ik)),nproc_egrp)&
-                  .eq.iproc ) THEN
-                count = count + 1
-                comm_recv(iproc+1,ik)%indices(count) = ig
-             END IF
-          END DO
-          !
-       END DO
-       !
-       ! allocate communication packets to send psi and hpsi
-       !
-       prev = 0
-       DO iproc=0, nproc_egrp-1
-          !
-          ! determine how many values need to be sent to iproc
-          !
-          count = 0
-          DO ig=1, lda_exx(iproc+1,ik)
-             IF ( MODULO(psi_source(ig+prev),nproc_egrp).eq.me_egrp ) THEN
-                count = count + 1
-             END IF
-          END DO
-          !
-          ! allocate the communication packet
-          !
-          comm_send(iproc+1,ik)%size = count
-          IF (count.gt.0) THEN
-             IF (.not.ALLOCATED(comm_send(iproc+1,ik)%msg)) THEN
-                ALLOCATE(comm_send(iproc+1,ik)%indices(count))
-                ALLOCATE(comm_send(iproc+1,ik)%msg(count,npol,max_ibands+2))
-             END IF
-          END IF
-          !
-          ! determine which values need to be sent to iproc
-          !
-          count = 0
-          DO ig=1, lda_exx(iproc+1,ik)
-             IF ( MODULO(psi_source(ig+prev),nproc_egrp).eq.me_egrp ) THEN
-                count = count + 1
-                comm_send(iproc+1,ik)%indices(count) = l2e_map(ig+prev,ik)
-             END IF
-          END DO
-          !
-          prev = prev + lda_exx(iproc+1,ik)
-          !
-       END DO
-       !
-    END DO
-    !
-    ! allocate psi_exx and hpsi_exx
-    !
-    IF(allocated(psi_exx))DEALLOCATE(psi_exx)
-    ALLOCATE(psi_exx(npwx*npol, max_ibands ))
-    IF(allocated(hpsi_exx))DEALLOCATE(hpsi_exx)
-    ALLOCATE(hpsi_exx(npwx*npol, max_ibands ))
-    !
-    ! allocate communication arrays for the exx to local transformation
-    !
-    IF ( .not.allocated(comm_recv_reverse) ) THEN
-       ALLOCATE(comm_recv_reverse(nproc_egrp,nks))
-       ALLOCATE(comm_send_reverse(nproc_egrp,negrp,nks))
-    END IF
-    !
-    egrp_base = my_egrp_id*nproc_egrp
-    DO ik = 1, nks
-       total_lda_egrp(ik) = &
-            sum( lda_local(egrp_base+1:(egrp_base+nproc_egrp),ik) )
-       prev_lda_egrp(ik) = &
-            sum( lda_local(egrp_base+1:(egrp_base+me_egrp),ik) )
-    END DO
-    !
-    max_lda_egrp = 0
-    DO j = 1, negrp
-       DO ik = 1, nks
-          max_lda_egrp = max(max_lda_egrp, &
-               sum( lda_local((j-1)*nproc_egrp+1:j*nproc_egrp,ik) ) )
-       END DO
-    END DO
-    !
-    ! determine the e2l_map
-    !
-    allocate( e2l_map(max_lda_egrp,nks,negrp) )
-    e2l_map = 0
-    DO ik = 1, nks
-       DO ig = 1, lda_local(me_pool+1,ik)
-          DO j=1, total_lda_exx(ik)
-             IF( local_map(ig+prev_lda(ik),ik).EQ.exx_map(j,ik) ) exit
-          END DO
-          e2l_map(ig+prev_lda_egrp(ik),ik,my_egrp_id+1) = j
-       END DO
-    END DO
-    CALL mp_sum(e2l_map(:,:,my_egrp_id+1),intra_egrp_comm)
-    CALL mp_sum(e2l_map,inter_egrp_comm)
-    !
-    ! plan communication for the local to EXX data structure transformation
-    !
-    allocate(psi_source_exx( max_lda_egrp, negrp ))
-    DO ik = 1, nks
-       !
-       ! determine where each value is coming from
-       !
-       psi_source_exx = 0
-       DO ig = 1, lda_local(me_pool+1,ik)
-          j = 1
-          DO i = 1, nproc_egrp
-             j = j + lda_exx(i,ik)
-             IF( j.gt.e2l_map(ig+prev_lda_egrp(ik),ik,my_egrp_id+1) ) exit
-          END DO
-          psi_source_exx(ig+prev_lda_egrp(ik),my_egrp_id+1) = i-1
-       END DO
-       CALL mp_sum(psi_source_exx(:,my_egrp_id+1),intra_egrp_comm)
-       CALL mp_sum(psi_source_exx,inter_egrp_comm)
-       !
-       ! allocate communication packets to receive psi and hpsi (reverse)
-       !
-       DO iegrp=my_egrp_id+1, my_egrp_id+1
-          DO iproc=0, nproc_egrp-1
-             !
-             ! determine how many values need to come from iproc
-             !
-             count = 0
-             DO ig=1, lda_local(me_pool+1,ik)
-                IF ( psi_source_exx(ig+prev_lda_egrp(ik),iegrp).eq.iproc ) THEN
-                   count = count + 1
-                END IF
-             END DO
-             !
-             ! allocate the communication packet
-             !
-             comm_recv_reverse(iproc+1,ik)%size = count
-             IF (count.gt.0) THEN
-                IF (.not.ALLOCATED(comm_recv_reverse(iproc+1,ik)%msg)) THEN
-                   ALLOCATE(comm_recv_reverse(iproc+1,ik)%indices(count))
-                   ALLOCATE(comm_recv_reverse(iproc+1,ik)%msg(count,npol,m+2))
-                END IF
-             END IF
-             !
-             ! determine which values need to come from iproc
-             !
-             count = 0
-             DO ig=1, lda_local(me_pool+1,ik)
-                IF ( psi_source_exx(ig+prev_lda_egrp(ik),iegrp).eq.iproc ) THEN
-                   count = count + 1
-                   comm_recv_reverse(iproc+1,ik)%indices(count) = ig
-                END IF
-             END DO
-             
-          END DO
-       END DO
-       !
-       ! allocate communication packets to send psi and hpsi
-       !
-       DO iegrp=1, negrp
-          prev = 0
-          DO iproc=0, nproc_egrp-1
-             !
-             ! determine how many values need to be sent to iproc
-             !
-             count = 0
-             DO ig=1, lda_local(iproc+(iegrp-1)*nproc_egrp+1,ik)
-                IF ( psi_source_exx(ig+prev,iegrp).eq.me_egrp ) THEN
-                   count = count + 1
-                END IF
-             END DO
-             !
-             ! allocate the communication packet
-             !
-             comm_send_reverse(iproc+1,iegrp,ik)%size = count
-             IF (count.gt.0) THEN
-                IF (.not.ALLOCATED(comm_send_reverse(iproc+1,iegrp,ik)%msg))THEN
-                   ALLOCATE(comm_send_reverse(iproc+1,iegrp,ik)%indices(count))
-                   ALLOCATE(comm_send_reverse(iproc+1,iegrp,ik)%msg(count,npol,&
-                        iexx_iend(my_egrp_id+1)-iexx_istart(my_egrp_id+1)+3))
-                END IF
-             END IF
-             !
-             ! determine which values need to be sent to iproc
-             !
-             count = 0
-             DO ig=1, lda_local(iproc+(iegrp-1)*nproc_egrp+1,ik)
-                IF ( psi_source_exx(ig+prev,iegrp).eq.me_egrp ) THEN
-                   count = count + 1
-                   comm_send_reverse(iproc+1,iegrp,ik)%indices(count) = &
-                        e2l_map(ig+prev,ik,iegrp)
-                END IF
-             END DO
-             !
-             prev = prev + lda_local( (iegrp-1)*nproc_egrp+iproc+1, ik )
-             !
-          END DO
-       END DO
-       !
-    END DO
-    !
-    ! deallocate arrays
-    !
-    DEALLOCATE( local_map, exx_map )
-    DEALLOCATE( l2e_map, e2l_map )
-    DEALLOCATE( psi_source, psi_source_exx )
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE initialize_local_to_exact_map
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE transform_to_exx(lda, n, m, m_out, ik, psi, psi_out, type)
-  !-----------------------------------------------------------------------
-    !
-    ! transform psi into the EXX data structure, and place the result in psi_out
-    !
-    USE wvfct,        ONLY : nbnd
-    USE mp,           ONLY : mp_sum
-    USE mp_pools,     ONLY : nproc_pool, me_pool
-    USE mp_exx,       ONLY : intra_egrp_comm, inter_egrp_comm, &
-         nproc_egrp, me_egrp, negrp, my_egrp_id, nibands, ibands, &
-         max_ibands, all_start, all_end
-    USE parallel_include
-    !
-    !
-    IMPLICIT NONE
-    !
-    Integer :: lda
-    INTEGER :: n, m, m_out
-    COMPLEX(DP) :: psi(npwx_local*npol,m) 
-    COMPLEX(DP) :: psi_out(npwx_exx*npol,m_out)
-    INTEGER, INTENT(in) :: type
-
-    COMPLEX(DP), ALLOCATABLE :: psi_work(:,:,:,:), psi_gather(:,:)
-    INTEGER :: i, j, im, iproc, ig, ik, iegrp
-    INTEGER :: prev, lda_max_local
-
-    INTEGER :: request_send(nproc_egrp), request_recv(nproc_egrp)
-    INTEGER :: ierr
-    INTEGER :: current_ik
-    !INTEGER, EXTERNAL :: find_current_k
-    INTEGER :: recvcount(negrp)
-    INTEGER :: displs(negrp)
-#if defined(__MPI)
-    INTEGER :: istatus(MPI_STATUS_SIZE)
-#endif
-    INTEGER :: requests(max_ibands+2,negrp)
-    !
-    INTEGER :: ipol, my_lda, lda_offset, count
-    lda_max_local = maxval(lda_local)
-    current_ik = ik
-    !
-    !-------------------------------------------------------!
-    !Communication Part 1
-    !-------------------------------------------------------!
-    !
-    allocate(psi_work(lda_max_local,npol,m,negrp))
-    allocate(psi_gather(lda_max_local*npol,m))
-    DO im=1, m
-       my_lda = lda_local(me_pool+1,current_ik)
-       DO ipol=1, npol
-          lda_offset = lda_max_local*(ipol-1)
-          DO ig=1, my_lda
-             psi_gather(lda_offset+ig,im) = psi(npwx_local*(ipol-1)+ig,im)
-          END DO
-       END DO
-    END DO
-    recvcount = lda_max_local*npol
-    count = lda_max_local*npol
-#if defined (__MPI_NONBLOCKING)
-    IF ( type.eq.0 ) THEN
-       DO iegrp=1, negrp
-          displs(iegrp) = (iegrp-1)*(count*m)
-       END DO
-       DO iegrp=1, negrp
-          DO im=1, nibands(iegrp)
-             IF ( my_egrp_id.eq.(iegrp-1) ) THEN
-                DO j=1, negrp
-                   displs(j) = (j-1)*(count*m) + count*(ibands(im,iegrp)-1)
-                END DO
-             END IF
-#if defined(__MPI)
-             CALL MPI_IGATHERV( psi_gather(:, ibands(im,iegrp) ), &
-                  count, MPI_DOUBLE_COMPLEX, &
-                  psi_work, &
-                  recvcount, displs, MPI_DOUBLE_COMPLEX, &
-                  iegrp-1, &
-                  inter_egrp_comm, requests(im,iegrp), ierr )
-#endif
-          END DO
-       END DO
-
-    ELSE IF(type.eq.1) THEN
-#elif defined(__MPI)
-       CALL MPI_ALLGATHER( psi_gather, &
-            count*m, MPI_DOUBLE_COMPLEX, &
-            psi_work, &
-            count*m, MPI_DOUBLE_COMPLEX, &
-            inter_egrp_comm, ierr )
-#endif
-
-#if defined (__MPI_NONBLOCKING)
-    ELSE IF(type.eq.2) THEN !evc2
-
-       DO iegrp=1, negrp
-          displs(iegrp) = (iegrp-1)*(count*m)
-       END DO
-       DO iegrp=1, negrp
-          DO im=1, all_end(iegrp) - all_start(iegrp) + 1
-             !
-             IF(all_start(iegrp).eq.0) CYCLE
-             !
-             IF ( my_egrp_id.eq.(iegrp-1) ) THEN
-                DO j=1, negrp
-                   displs(j) = (j-1)*(count*m) + count*(im+all_start(iegrp)-2)
-                END DO
-             END IF
-#if defined(__MPI)
-             CALL MPI_IGATHERV( psi_gather(:, im+all_start(iegrp)-1 ), &
-                  count, MPI_DOUBLE_COMPLEX, &
-                  psi_work, &
-                  recvcount, displs, MPI_DOUBLE_COMPLEX, &
-                  iegrp-1, &
-                  inter_egrp_comm, requests(im,iegrp), ierr )
-#endif
-          END DO
-       END DO
-          
-    END IF
-    !
-    IF(type.eq.0)THEN
-       DO iegrp=1, negrp
-          DO im=1, nibands(iegrp)
-             CALL MPI_WAIT(requests(im,iegrp), istatus, ierr)
-          END DO
-       END DO
-    ELSEIF(type.eq.2)THEN
-       DO iegrp=1, negrp
-          DO im=1, all_end(iegrp) - all_start(iegrp) + 1
-             IF(all_start(iegrp).eq.0) CYCLE
-             CALL MPI_WAIT(requests(im,iegrp), istatus, ierr)
-          END DO
-       END DO
-    END IF
-#endif
-    !
-    !-------------------------------------------------------!
-    !Communication Part 2
-    !-------------------------------------------------------!
-    !
-    !send communication packets
-    !
-    DO iproc=0, nproc_egrp-1
-       IF ( comm_send(iproc+1,current_ik)%size.gt.0) THEN
-          DO i=1, comm_send(iproc+1,current_ik)%size
-             ig = comm_send(iproc+1,current_ik)%indices(i)
-             !
-             !determine which egrp this corresponds to
-             !
-             prev = 0
-             DO j=1, nproc_pool
-                IF ((prev+lda_local(j,current_ik)).ge.ig) THEN 
-                   ig = ig - prev
-                   exit
-                END IF
-                prev = prev + lda_local(j,current_ik)
-             END DO
-             !
-             ! prepare the message
-             !
-             DO ipol=1, npol
-             IF ( type.eq.0 ) THEN !psi or hpsi
-                DO im=1, nibands(my_egrp_id+1)
-                   comm_send(iproc+1,current_ik)%msg(i,ipol,im) = &
-                        psi_work(ig,ipol,ibands(im,my_egrp_id+1),1+(j-1)/nproc_egrp)
-                END DO
-             ELSE IF (type.eq.1) THEN !evc
-                DO im=1, m
-                   comm_send(iproc+1,current_ik)%msg(i,ipol,im) = &
-                        psi_work(ig,ipol,im,1+(j-1)/nproc_egrp)
-                END DO
-             ELSE IF ( type.eq.2 ) THEN !evc2
-                IF(all_start(my_egrp_id+1).gt.0) THEN
-                   DO im=1, all_end(my_egrp_id+1) - all_start(my_egrp_id+1) + 1
-                      comm_send(iproc+1,current_ik)%msg(i,ipol,im) = &
-                           psi_work(ig,ipol,im+all_start(my_egrp_id+1)-1,1+(j-1)/nproc_egrp)
-                   END DO
-                END IF
-             END IF
-             END DO
-             !
-          END DO
-          !
-          ! send the message
-          !
-#if defined(__MPI)
-          IF ( type.eq.0 ) THEN !psi or hpsi
-             CALL MPI_ISEND( comm_send(iproc+1,current_ik)%msg, &
-                  comm_send(iproc+1,current_ik)%size*npol*nibands(my_egrp_id+1), &
-                  MPI_DOUBLE_COMPLEX, &
-                  iproc, 100+iproc*nproc_egrp+me_egrp, &
-                  intra_egrp_comm, request_send(iproc+1), ierr )
-          ELSE IF (type.eq.1) THEN !evc
-             CALL MPI_ISEND( comm_send(iproc+1,current_ik)%msg, &
-                  comm_send(iproc+1,current_ik)%size*npol*m, MPI_DOUBLE_COMPLEX, &
-                  iproc, 100+iproc*nproc_egrp+me_egrp, &
-                  intra_egrp_comm, request_send(iproc+1), ierr )
-          ELSE IF (type.eq.2) THEN !evc2
-             CALL MPI_ISEND( comm_send(iproc+1,current_ik)%msg, &
-                  comm_send(iproc+1,current_ik)%size*npol*(all_end(my_egrp_id+1)-all_start(my_egrp_id+1)+1), &
-                  MPI_DOUBLE_COMPLEX, &
-                  iproc, 100+iproc*nproc_egrp+me_egrp, &
-                  intra_egrp_comm, request_send(iproc+1), ierr )
-          END IF
-#endif
-          !
-       END IF
-    END DO
-    !
-    ! begin receiving the messages
-    !
-    DO iproc=0, nproc_egrp-1
-       IF ( comm_recv(iproc+1,current_ik)%size.gt.0) THEN
-          !
-          ! receive the message
-          !
-#if defined(__MPI)
-          IF (type.eq.0) THEN !psi or hpsi
-             CALL MPI_IRECV( comm_recv(iproc+1,current_ik)%msg, &
-                  comm_recv(iproc+1,current_ik)%size*npol*nibands(my_egrp_id+1), &
-                  MPI_DOUBLE_COMPLEX, &
-                  iproc, 100+me_egrp*nproc_egrp+iproc, &
-                  intra_egrp_comm, request_recv(iproc+1), ierr )
-          ELSE IF (type.eq.1) THEN !evc
-             CALL MPI_IRECV( comm_recv(iproc+1,current_ik)%msg, &
-                  comm_recv(iproc+1,current_ik)%size*npol*m, MPI_DOUBLE_COMPLEX, &
-                  iproc, 100+me_egrp*nproc_egrp+iproc, &
-                  intra_egrp_comm, request_recv(iproc+1), ierr )
-          ELSE IF (type.eq.2) THEN !evc2
-             CALL MPI_IRECV( comm_recv(iproc+1,current_ik)%msg, &
-                  comm_recv(iproc+1,current_ik)%size*npol*(all_end(my_egrp_id+1)-all_start(my_egrp_id+1)+1), &
-                  MPI_DOUBLE_COMPLEX, &
-                  iproc, 100+me_egrp*nproc_egrp+iproc, &
-                  intra_egrp_comm, request_recv(iproc+1), ierr )
-          END IF
-#endif
-          !
-       END IF
-    END DO
-    !
-    ! assign psi_out
-    !
-    DO iproc=0, nproc_egrp-1
-       IF ( comm_recv(iproc+1,current_ik)%size.gt.0 ) THEN
-          !
-          ! wait for the message to be received
-          !
-#if defined(__MPI)
-          CALL MPI_WAIT(request_recv(iproc+1), istatus, ierr)
-#endif
-          !
-          DO i=1, comm_recv(iproc+1,current_ik)%size
-             ig = comm_recv(iproc+1,current_ik)%indices(i)
-             !
-             ! place the message into the correct elements of psi_out
-             !
-             IF (type.eq.0) THEN !psi or hpsi
-                DO im=1, nibands(my_egrp_id+1)
-                   DO ipol=1, npol
-                      psi_out(ig+npwx_exx*(ipol-1),im) = &
-                           comm_recv(iproc+1,current_ik)%msg(i,ipol,im)
-                   END DO
-                END DO
-             ELSE IF (type.eq.1) THEN !evc
-                DO im=1, m
-                   DO ipol=1, npol
-                      psi_out(ig+npwx_exx*(ipol-1),im) = &
-                           comm_recv(iproc+1,current_ik)%msg(i,ipol,im)
-                   END DO
-                END DO
-             ELSE IF (type.eq.2) THEN !evc2
-                DO im=1, all_end(my_egrp_id+1) - all_start(my_egrp_id+1) + 1
-                   DO ipol=1, npol
-                      psi_out(ig+npwx_exx*(ipol-1),im) = comm_recv(iproc+1,current_ik)%msg(i,ipol,im)
-                   END DO
-                END DO
-             END IF
-             !
-          END DO
-          !
-       END IF
-    END DO
-    !
-    ! wait for everything to finish sending
-    !
-#if defined(__MPI)
-    DO iproc=0, nproc_egrp-1
-       IF ( comm_send(iproc+1,current_ik)%size.gt.0 ) THEN
-          CALL MPI_WAIT(request_send(iproc+1), istatus, ierr)
-       END IF
-    END DO
-#endif
-    !
-    ! deallocate arrays
-    !
-    DEALLOCATE( psi_work, psi_gather )
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE transform_to_exx
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE change_data_structure(is_exx)
-  !-----------------------------------------------------------------------
-    !
-    ! change between the local and EXX data structures
-    ! is_exx = .TRUE. - change to the EXX data structure
-    ! is_exx = .FALSE. - change to the local data strucutre
-    !
-    USE cell_base,      ONLY : at, bg, tpiba2
-    USE cellmd,         ONLY : lmovecell
-    USE wvfct,          ONLY : npwx
-    USE gvect,          ONLY : gcutm, ig_l2g, g, gg, ngm, ngm_g, mill, &
-                               gstart, gvect_init, deallocate_gvect_exx
-    USE gvecs,          ONLY : gcutms, ngms, ngms_g, gvecs_init
-    USE gvecw,          ONLY : gkcut, ecutwfc, gcutw
-    USE klist,          ONLY : xk, nks, ngk
-    USE mp_bands,       ONLY : intra_bgrp_comm, ntask_groups, nyfft
-    USE mp_exx,         ONLY : intra_egrp_comm, me_egrp, exx_mode, nproc_egrp, &
-                               negrp, root_egrp
-    USE io_global,      ONLY : stdout
-    USE fft_base,       ONLY : dfftp, dffts, smap, fft_base_info
-    USE fft_types,      ONLY : fft_type_init
-    USE recvec_subs,    ONLY : ggen, ggens
-!    USE task_groups,    ONLY : task_groups_init
-    !
-    !
-    IMPLICIT NONE
-    !
-    LOGICAL, intent(in) :: is_exx
-    INTEGER, EXTERNAL  :: n_plane_waves
-    COMPLEX(DP), ALLOCATABLE :: work_space(:)
-    INTEGER :: ik, i
-    INTEGER :: ngm_, ngs_, ngw_
-    LOGICAL exst
-#if defined (__MPI)
-  LOGICAL :: lpara = .true.
-#else
-  LOGICAL :: lpara = .false.
-#endif
-    !
-    IF (negrp.eq.1) RETURN
-    !
-    IF (first_data_structure_change) THEN
-       allocate( ig_l2g_loc(ngm), g_loc(3,ngm), gg_loc(ngm) )
-       allocate( mill_loc(3,ngm), nl_loc(ngm) )
-       allocate( nls_loc(size(dffts%nl)) )
-       IF ( gamma_only) THEN
-          allocate( nlm_loc(size(dfftp%nlm)) )
-          allocate( nlsm_loc(size(dffts%nlm)) )
-       END IF
-       ig_l2g_loc = ig_l2g
-       g_loc = g
-       gg_loc = gg
-       mill_loc = mill
-       nl_loc = dfftp%nl
-       nls_loc = dffts%nl
-       IF ( gamma_only) THEN
-          nlm_loc = dfftp%nlm
-          nlsm_loc = dffts%nlm
-       END IF
-       ngm_loc = ngm
-       ngm_g_loc = ngm_g
-       gstart_loc = gstart
-       ngms_loc = ngms
-       ngms_g_loc = ngms_g
-    END IF
-    !
-    ! generate the gvectors for the new data structure
-    !
-    IF (is_exx) THEN
-       exx_mode = 1
-       IF(first_data_structure_change)THEN
-          dfftp_loc = dfftp
-          dffts_loc = dffts
-
-          CALL fft_type_init( dffts_exx, smap_exx, "wave", gamma_only, &
-               lpara, intra_egrp_comm, at, bg, gkcut, gcutms/gkcut, &
-               nyfft=ntask_groups )
-          CALL fft_type_init( dfftp_exx, smap_exx, "rho", gamma_only, &
-               lpara, intra_egrp_comm, at, bg,  gcutm, nyfft=nyfft )
-          CALL fft_base_info( ionode, stdout )
-          ngs_ = dffts_exx%ngl( dffts_exx%mype + 1 )
-          ngm_ = dfftp_exx%ngl( dfftp_exx%mype + 1 )
-          IF( gamma_only ) THEN
-             ngs_ = (ngs_ + 1)/2
-             ngm_ = (ngm_ + 1)/2
-          END IF
-          dfftp = dfftp_exx
-          dffts = dffts_exx
-          ngm = ngm_
-          ngms = ngs_
-       ELSE
-          dfftp = dfftp_exx
-          dffts = dffts_exx
-          ngm = ngm_exx
-          ngms = ngms_exx
-       END IF
-       call deallocate_gvect_exx()
-       call gvect_init( ngm , intra_egrp_comm )
-       call gvecs_init( ngms , intra_egrp_comm )
-    ELSE
-       exx_mode = 2
-       dfftp = dfftp_loc
-       dffts = dffts_loc
-       ngm = ngm_loc
-       ngms = ngms_loc
-       call deallocate_gvect_exx()
-       call gvect_init( ngm , intra_bgrp_comm )
-       call gvecs_init( ngms , intra_bgrp_comm )
-       exx_mode = 0
-    END IF
-    !
-    IF (first_data_structure_change) THEN
-       CALL ggen ( dfftp, gamma_only, at, bg, gcutm, ngm_g, ngm, &
-            g, gg, mill, ig_l2g, gstart )
-       CALL ggens( dffts, gamma_only, at, g, gg, mill, gcutms, ngms )
-       allocate( ig_l2g_exx(ngm), g_exx(3,ngm), gg_exx(ngm) )
-       allocate( mill_exx(3,ngm), nl_exx(ngm) )
-       allocate( nls_exx(size(dffts%nl)) )
-       allocate( nlm_exx(size(dfftp%nlm) ) )
-       allocate( nlsm_exx(size(dffts%nlm) ) )
-       ig_l2g_exx = ig_l2g
-       g_exx = g
-       gg_exx = gg
-       mill_exx = mill
-       nl_exx = dfftp%nl
-       nls_exx = dffts%nl
-       IF( gamma_only ) THEN
-          nlm_exx = dfftp%nlm
-          nlsm_exx = dffts%nlm
-       END IF
-       ngm_exx = ngm
-       ngm_g_exx = ngm_g
-       gstart_exx = gstart
-       ngms_exx = ngms
-       ngms_g_exx = ngms_g
-    ELSE IF ( is_exx ) THEN
-       ig_l2g = ig_l2g_exx
-       g = g_exx
-       gg = gg_exx
-       mill = mill_exx
-       ! workaround: here dfft?%nl* are unallocated
-       ! some compilers go on and allocate, some others crash
-       IF ( .NOT. ALLOCATED(dfftp%nl) ) ALLOCATE (dfftp%nl(size(nl_exx)))
-       IF ( .NOT. ALLOCATED(dffts%nl) ) ALLOCATE (dffts%nl(size(nls_exx)))
-       IF ( gamma_only .AND. .NOT.ALLOCATED(dfftp%nlm) ) ALLOCATE (dfftp%nlm(size(nlm_exx)))
-       IF ( gamma_only .AND. .NOT.ALLOCATED(dffts%nlm) ) ALLOCATE (dffts%nlm(size(nlsm_exx)))
-       ! end workaround. FIXME: this part of code must disappear ASAP
-       dfftp%nl = nl_exx
-       dffts%nl = nls_exx
-       IF( gamma_only ) THEN
-          dfftp%nlm = nlm_exx
-          dffts%nlm = nlsm_exx
-       ENDIF
-       ngm = ngm_exx
-       ngm_g = ngm_g_exx
-       gstart = gstart_exx
-       ngms = ngms_exx
-       ngms_g = ngms_g_exx
-    ELSE ! not is_exx
-       ig_l2g = ig_l2g_loc
-       g = g_loc
-       gg = gg_loc
-       mill = mill_loc
-       dfftp%nl = nl_loc
-       dffts%nl = nls_loc
-       IF( gamma_only ) THEN
-          dfftp%nlm = nlm_loc
-          dffts%nlm = nlsm_loc
-       END IF
-       ngm = ngm_loc
-       ngm_g = ngm_g_loc
-       gstart = gstart_loc
-       ngms = ngms_loc
-       ngms_g = ngms_g_loc
-    END IF
-    !
-    ! get npwx and ngk
-    !
-    IF ( is_exx.and.npwx_exx.gt.0 ) THEN
-       npwx = npwx_exx
-       ngk = ngk_exx
-    ELSE IF ( .not.is_exx.and.npwx_local.gt.0 ) THEN
-       npwx = npwx_local
-       ngk = ngk_local
-    ELSE
-       npwx = n_plane_waves (gcutw, nks, xk, g, ngm)
-    END IF
-    !
-    ! get igk
-    !
-    IF( first_data_structure_change ) THEN
-       allocate(igk_exx(npwx,nks),work_space(npwx))
-       first_data_structure_change = .FALSE.
-       IF ( nks.eq.1 ) THEN
-          CALL gk_sort( xk, ngm, g, ecutwfc / tpiba2, ngk, igk_exx, work_space )
-       END IF
-       IF ( nks > 1 ) THEN
-          !
-          DO ik = 1, nks
-             CALL gk_sort( xk(1,ik), ngm, g, ecutwfc / tpiba2, ngk(ik), &
-                  igk_exx(1,ik), work_space )
-          END DO
-          !
-       END IF
-       DEALLOCATE( work_space )
-    END IF
-    !
-    ! generate ngl and igtongl
-    !
-    CALL gshells( lmovecell )
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE change_data_structure
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE update_igk(is_exx)
-  !-----------------------------------------------------------------------
-    USE cell_base,      ONLY : tpiba2
-    USE gvect,          ONLY : ngm, g
-    USE gvecw,          ONLY : ecutwfc
-    USE wvfct,          ONLY : npwx, current_k
-    USE klist,          ONLY : xk, igk_k
-    USE mp_exx,         ONLY : negrp
-    !
-    !
-    IMPLICIT NONE
-    !
-    LOGICAL, intent(in) :: is_exx
-    COMPLEX(DP), ALLOCATABLE :: work_space(:)
-    INTEGER :: comm
-    INTEGER :: npw, ik, i
-    LOGICAL exst
-    !
-    IF (negrp.eq.1) RETURN
-    !
-    ! get igk
-    !
-    allocate(work_space(npwx))
-    ik = current_k
-    IF(is_exx) THEN
-       CALL gk_sort( xk(1,ik), ngm, g, ecutwfc / tpiba2, npw, igk_exx(1,ik), &
-            work_space )
-    ELSE
-       CALL gk_sort( xk(1,ik), ngm, g, ecutwfc / tpiba2, npw, igk_k(1,ik), &
-            work_space )
-    END IF
-    !
-    DEALLOCATE( work_space )
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE update_igk
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE result_sum (n, m, data)
-  !-----------------------------------------------------------------------
-    USE parallel_include
-    USE mp_exx,       ONLY : iexx_start, iexx_end, inter_egrp_comm, &
-                               intra_egrp_comm, my_egrp_id, negrp, &
-                               max_pairs, egrp_pairs, max_contributors, &
-                               contributed_bands, all_end, &
-                               iexx_istart, iexx_iend, band_roots
-    USE mp,           ONLY : mp_sum, mp_bcast
-
-    INTEGER, INTENT(in) :: n, m
-    COMPLEX(DP), INTENT(inout) :: data(n,m)
-#if defined(__MPI)
-    INTEGER :: istatus(MPI_STATUS_SIZE)
-    COMPLEX(DP), ALLOCATABLE :: recvbuf(:,:)
-    COMPLEX(DP) :: data_sum(n,m), test(negrp)
-    INTEGER :: im, iegrp, ibuf, i, j, nsending(m)
-    INTEGER :: ncontributing(m)
-    INTEGER :: contrib_this(negrp,m), displs(negrp,m)
-
-    INTEGER sendcount, sendtype, ierr, root, request(m)
-    INTEGER sendc(negrp), sendd(negrp)
-#endif
-    !
-    IF (negrp.eq.1) RETURN
-    !
-#if defined(__MPI)
-    ! gather data onto the correct nodes
-    !
-    ALLOCATE( recvbuf( n*max_contributors, max(1,iexx_end-iexx_start+1) ) )
-    displs = 0
-    ibuf = 0
-    nsending = 0
-    contrib_this = 0
-    !
-    DO im=1, m
-       !
-       IF(contributed_bands(im,my_egrp_id+1)) THEN
-          sendcount = n
-       ELSE
-          sendcount = 0
-       END IF
-       !
-       root = band_roots(im)
-       !
-       IF(my_egrp_id.eq.root) THEN
-          !
-          ! determine the number of sending processors
-          !
-          ibuf = ibuf + 1
-          ncontributing(im) = 0
-          DO iegrp=1, negrp
-             IF(contributed_bands(im,iegrp)) THEN
-                ncontributing(im) = ncontributing(im) + 1
-                contrib_this(iegrp,im) = n
-                IF(iegrp.lt.negrp) displs(iegrp+1,im) = displs(iegrp,im) + n
-                nsending(im) = nsending(im) + 1
-             ELSE
-                contrib_this(iegrp,im) = 0
-                IF(iegrp.lt.negrp) displs(iegrp+1,im) = displs(iegrp,im)
-             END IF
-          END DO
-       END IF
-       !
-#if defined(__MPI_NONBLOCKING)
-       CALL MPI_IGATHERV(data(:,im), sendcount, MPI_DOUBLE_COMPLEX, &
-            recvbuf(:,max(1,ibuf)), contrib_this(:,im), &
-            displs(:,im), MPI_DOUBLE_COMPLEX, &
-            root, inter_egrp_comm, request(im), ierr)
-#else
-       CALL MPI_GATHERV(data(:,im), sendcount, MPI_DOUBLE_COMPLEX, &
-            recvbuf(:,max(1,ibuf)), contrib_this(:,im), &
-            displs(:,im), MPI_DOUBLE_COMPLEX, &
-            root, inter_egrp_comm, ierr)
-#endif
-       !
-    END DO
-    !
-#if defined(__MPI_NONBLOCKING)
-    DO im=1, m
-       CALL MPI_WAIT(request(im), istatus, ierr)
-    END DO
-#endif
-    !
-    ! perform the sum
-    !
-    DO im=iexx_istart(my_egrp_id+1), iexx_iend(my_egrp_id+1)
-       IF(im.eq.0)exit
-       data(:,im) = 0._dp
-       ibuf = im - iexx_istart(my_egrp_id+1) + 1
-       DO j=1, nsending(im)
-          DO i=1, n
-             data(i,im) = data(i,im) + recvbuf(i+n*(j-1),ibuf)
-          END DO
-       END DO
-    END DO
-#endif
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE result_sum
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE transform_to_local(m, m_exx, psi, psi_out)
-  !-----------------------------------------------------------------------
-    USE mp,           ONLY : mp_sum
-    USE mp_pools,     ONLY : nproc_pool, me_pool, intra_pool_comm
-    USE mp_exx,       ONLY : intra_egrp_comm, inter_egrp_comm, &
-         nproc_egrp, me_egrp, negrp, my_egrp_id, iexx_istart, iexx_iend
-    USE parallel_include
-    USE wvfct,        ONLY : current_k
-    !
-    !
-    IMPLICIT NONE
-    !
-    INTEGER :: m, m_exx
-    COMPLEX(DP) :: psi(npwx_exx*npol,m_exx)
-    COMPLEX(DP) :: psi_out(npwx_local*npol,m)
-    !
-    INTEGER :: i, j, im, iproc, ig, ik, current_ik, iegrp
-    INTEGER :: prev, lda_max_local, prev_lda_exx
-    INTEGER :: my_bands, recv_bands, tag
-    !
-    INTEGER :: request_send(nproc_egrp,negrp), request_recv(nproc_egrp,negrp)
-    INTEGER :: ierr
-    INTEGER :: ipol
-#if defined(__MPI)
-    INTEGER :: istatus(MPI_STATUS_SIZE)
-#endif
-    !INTEGER, EXTERNAL :: find_current_k
-    !
-    current_ik = current_k
-    prev_lda_exx = sum( lda_exx(1:me_egrp,current_ik) )
-    !
-    my_bands = iexx_iend(my_egrp_id+1) - iexx_istart(my_egrp_id+1) + 1
-    !
-    ! send communication packets
-    !
-    IF ( iexx_istart(my_egrp_id+1).gt.0 ) THEN
-       DO iegrp=1, negrp
-          DO iproc=0, nproc_egrp-1
-             IF ( comm_send_reverse(iproc+1,iegrp,current_ik)%size.gt.0) THEN
-                DO i=1, comm_send_reverse(iproc+1,iegrp,current_ik)%size
-                   ig = comm_send_reverse(iproc+1,iegrp,current_ik)%indices(i)
-                   ig = ig - prev_lda_exx
-                   !
-                   DO im=1, my_bands
-                      DO ipol=1, npol
-                         comm_send_reverse(iproc+1,iegrp,current_ik)%msg(i,ipol,im) = &
-                              psi(ig+npwx_exx*(ipol-1),im)
-                      END DO
-                   END DO
-                   !
-                END DO
-                !
-                ! send the message
-                !
-                tag = 0
-#if defined(__MPI)
-                CALL MPI_ISEND( comm_send_reverse(iproc+1,iegrp,current_ik)%msg, &
-                     comm_send_reverse(iproc+1,iegrp,current_ik)%size*npol*my_bands, &
-                     MPI_DOUBLE_COMPLEX, &
-                     iproc+(iegrp-1)*nproc_egrp, &
-                     tag, &
-                     intra_pool_comm, request_send(iproc+1,iegrp), ierr )
-#endif
-                !
-             END IF
-          END DO
-       END DO
-    END IF
-    !
-    ! begin receiving the communication packets
-    !
-    DO iegrp=1, negrp
-       !
-       IF ( iexx_istart(iegrp).le.0 ) CYCLE
-       !
-       recv_bands = iexx_iend(iegrp) - iexx_istart(iegrp) + 1
-       !
-       DO iproc=0, nproc_egrp-1
-          IF ( comm_recv_reverse(iproc+1,current_ik)%size.gt.0) THEN
-             !
-             !receive the message
-             !
-             tag = 0
-#if defined(__MPI)
-             CALL MPI_IRECV( comm_recv_reverse(iproc+1,current_ik)%msg(:,:,iexx_istart(iegrp)), &
-                  comm_recv_reverse(iproc+1,current_ik)%size*npol*recv_bands, &
-                  MPI_DOUBLE_COMPLEX, &
-                  iproc+(iegrp-1)*nproc_egrp, &
-                  tag, &
-                  intra_pool_comm, request_recv(iproc+1,iegrp), ierr )
-#endif
-             !
-          END IF
-       END DO
-    END DO
-    !
-    ! assign psi
-    !
-    DO iproc=0, nproc_egrp-1
-       IF ( comm_recv_reverse(iproc+1,current_ik)%size.gt.0 ) THEN
-          !
-#if defined(__MPI)
-          DO iegrp=1, negrp
-             IF ( iexx_istart(iegrp).le.0 ) CYCLE
-             CALL MPI_WAIT(request_recv(iproc+1,iegrp), istatus, ierr)
-          END DO
-#endif
-          !
-          DO i=1, comm_recv_reverse(iproc+1,current_ik)%size
-             ig = comm_recv_reverse(iproc+1,current_ik)%indices(i)
-             !
-             ! set psi_out
-             !
-             DO im=1, m
-                DO ipol=1, npol
-                   psi_out(ig+npwx_local*(ipol-1),im) = psi_out(ig+npwx_local*(ipol-1),im) + &
-                        comm_recv_reverse(iproc+1,current_ik)%msg(i,ipol,im)
-                END DO
-             END DO
-             !
-          END DO
-          !
-       END IF
-    END DO
-    !
-    ! wait for everything to finish sending
-    !
-#if defined(__MPI)
-    IF ( iexx_istart(my_egrp_id+1).gt.0 ) THEN
-       DO iproc=0, nproc_egrp-1
-          DO iegrp=1, negrp
-             IF ( comm_send_reverse(iproc+1,iegrp,current_ik)%size.gt.0 ) THEN
-                CALL MPI_WAIT(request_send(iproc+1,iegrp), istatus, ierr)
-             END IF
-          END DO
-       END DO
-    END IF
-#endif
-    !
-    !-----------------------------------------------------------------------
-  END SUBROUTINE transform_to_local
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE exxbuff_comm(exxtemp,ikq,lda,jstart,jend)
-  !-----------------------------------------------------------------------
-    USE mp_exx,               ONLY : my_egrp_id, inter_egrp_comm, jblock, &
-                                     all_end, negrp
-    USE mp,             ONLY : mp_bcast
-    USE parallel_include
-    COMPLEX(DP), intent(inout) :: exxtemp(lda,jend-jstart+1)
-    INTEGER, intent(in) :: ikq, lda, jstart, jend
-    INTEGER :: jbnd, iegrp, ierr, request_exxbuff(jend-jstart+1)
-#if defined(__MPI)
-    INTEGER :: istatus(MPI_STATUS_SIZE)
-#endif
-
-    DO jbnd=jstart, jend
-       !determine which band group has this value of exxbuff
-       DO iegrp=1, negrp
-          IF(all_end(iegrp) >= jbnd) exit
-       END DO
-
-       IF (iegrp == my_egrp_id+1) THEN
-          exxtemp(:,jbnd-jstart+1) = exxbuff(:,jbnd,ikq)
-       END IF
-
-#if defined(__MPI_NONBLOCKING)
-       CALL MPI_IBCAST(exxtemp(:,jbnd-jstart+1), &
-            lda, &
-            MPI_DOUBLE_COMPLEX, &
-            iegrp-1, &
-            inter_egrp_comm, &
-            request_exxbuff(jbnd-jstart+1), ierr)
-#elif defined(__MPI)
-       CALL mp_bcast(exxtemp(:,jbnd-jstart+1),iegrp-1,inter_egrp_comm)
-#endif
-    END DO
-
-    DO jbnd=jstart, jend
-#if defined(__MPI_NONBLOCKING)
-       CALL MPI_WAIT(request_exxbuff(jbnd-jstart+1), istatus, ierr)
-#endif
-    END DO
-
-  !
-  !-----------------------------------------------------------------------
-  END SUBROUTINE exxbuff_comm
-  !-----------------------------------------------------------------------
-  !
-  !-----------------------------------------------------------------------
-  SUBROUTINE exxbuff_comm_gamma(exxtemp,ikq,lda,jstart,jend,jlength)
-  !-----------------------------------------------------------------------
-    USE mp_exx,               ONLY : my_egrp_id, inter_egrp_comm, jblock, &
-                                     all_end, negrp
-    USE mp,             ONLY : mp_bcast
-    USE parallel_include
-    COMPLEX(DP), intent(inout) :: exxtemp(lda*npol,jlength)
-    INTEGER, intent(in) :: ikq, lda, jstart, jend, jlength
-    INTEGER :: jbnd, iegrp, ierr, request_exxbuff(jend-jstart+1), ir
-#if defined(__MPI)
-    INTEGER :: istatus(MPI_STATUS_SIZE)
-#endif
-    REAL(DP), ALLOCATABLE :: work(:,:)
-
-    CALL start_clock ('comm_buff')
-
-    ALLOCATE ( work(lda*npol,jend-jstart+1) )
-    DO jbnd=jstart, jend
-       !determine which band group has this value of exxbuff
-       DO iegrp=1, negrp
-          IF(all_end(iegrp) >= jbnd) exit
-       END DO
-
-       IF (iegrp == my_egrp_id+1) THEN
-!          exxtemp(:,jbnd-jstart+1) = exxbuff(:,jbnd,ikq)
-          IF( MOD(jbnd,2) == 1 ) THEN
-             work(:,jbnd-jstart+1) = REAL(exxbuff(:,jbnd/2+1,ikq))
-          ELSE
-             work(:,jbnd-jstart+1) = AIMAG(exxbuff(:,jbnd/2,ikq))
-          END IF
-       END IF
-
-#if defined(__MPI_NONBLOCKING)
-       CALL MPI_IBCAST(work(:,jbnd-jstart+1), &
-            lda*npol, &
-            MPI_DOUBLE_PRECISION, &
-            iegrp-1, &
-            inter_egrp_comm, &
-            request_exxbuff(jbnd-jstart+1), ierr)
-#elif defined(__MPI)
-       CALL mp_bcast(work(:,jbnd-jstart+1),iegrp-1,inter_egrp_comm)
-#endif
-    END DO
-
-    DO jbnd=jstart, jend
-#if defined(__MPI_NONBLOCKING)
-       CALL MPI_WAIT(request_exxbuff(jbnd-jstart+1), istatus, ierr)
-#endif
-    END DO
-    DO jbnd=jstart, jend, 2
-       IF (jbnd < jend) THEN
-          ! two real bands can be coupled into a single complex one
-          DO ir=1, lda*npol
-             exxtemp(ir,1+(jbnd-jstart+1)/2) = CMPLX( work(ir,jbnd-jstart+1),&
-                                                      work(ir,jbnd-jstart+2),&
-                                                      KIND=dp )
-          END DO
-       ELSE
-          ! case of lone last band
-          DO ir=1, lda*npol
-             exxtemp(ir,1+(jbnd-jstart+1)/2) = CMPLX( work(ir,jbnd-jstart+1),&
-                                                      0.0_dp, KIND=dp )
-          END DO
-       ENDIF
-    END DO
-    DEALLOCATE ( work )
-
-    CALL stop_clock ('comm_buff')
-  !
-  !-----------------------------------------------------------------------
-  END SUBROUTINE exxbuff_comm_gamma
-  !-----------------------------------------------------------------------
 
 SUBROUTINE aceinit( exex )
   !
diff --git a/PW/src/exx_band.f90 b/PW/src/exx_band.f90
new file mode 100644
index 000000000..98c271281
--- /dev/null
+++ b/PW/src/exx_band.f90
@@ -0,0 +1,1558 @@
+! Copyright (C) 2005-2018 Quantum ESPRESSO group
+! This file is distributed under the terms of the
+! GNU General Public License. See the file `License'
+! in the root directory of the present distribution,
+! or http://www.gnu.org/copyleft/gpl.txt .
+!
+!--------------------------------------
+MODULE exx_band
+  !--------------------------------------
+  !
+  ! Variables and subroutines for band parallelization over pairs of bands:
+  ! see T. Barnes, T. Kurth, P. Carrier, N. Wichmann, D. Prendergast,
+  ! P.R.C. Kent, J. Deslippe, Computer Physics Communications 2017,
+  ! dx.doi.org/10.1016/j.cpc.2017.01.008
+  !
+  USE kinds,                ONLY : DP
+  USE noncollin_module,     ONLY : npol
+  USE io_global,            ONLY : ionode, stdout
+  !
+  USE control_flags,        ONLY : gamma_only
+  USE fft_types,            ONLY : fft_type_descriptor
+  USE stick_base,           ONLY : sticks_map
+  !
+  IMPLICIT NONE
+  SAVE
+  !!
+  COMPLEX(DP), ALLOCATABLE :: evc_exx(:,:)
+  COMPLEX(DP), ALLOCATABLE :: psi_exx(:,:), hpsi_exx(:,:)
+  INTEGER :: lda_original, n_original
+  INTEGER :: nwordwfc_exx
+  INTEGER, ALLOCATABLE :: igk_exx(:,:)
+  !
+  ! mapping for the data structure conversion
+  !
+  TYPE comm_packet
+     INTEGER :: size
+     INTEGER, ALLOCATABLE :: indices(:)
+     COMPLEX(DP), ALLOCATABLE :: msg(:,:,:)
+  END TYPE comm_packet
+  TYPE(comm_packet), ALLOCATABLE :: comm_recv(:,:), comm_send(:,:)
+  TYPE(comm_packet), ALLOCATABLE :: comm_recv_reverse(:,:)
+  TYPE(comm_packet), ALLOCATABLE :: comm_send_reverse(:,:,:)
+  INTEGER, ALLOCATABLE :: lda_local(:,:)
+  INTEGER, ALLOCATABLE :: lda_exx(:,:)
+  INTEGER, ALLOCATABLE :: ngk_local(:), ngk_exx(:)
+  INTEGER :: npwx_local = 0
+  INTEGER :: npwx_exx = 0
+  INTEGER :: n_local = 0
+  LOGICAL :: first_data_structure_change = .TRUE.
+
+  INTEGER :: ngm_loc, ngm_g_loc, gstart_loc
+  INTEGER, ALLOCATABLE :: ig_l2g_loc(:)
+  REAL(DP), ALLOCATABLE :: g_loc(:,:), gg_loc(:)
+  INTEGER, ALLOCATABLE :: mill_loc(:,:), nl_loc(:)
+  INTEGER :: ngms_loc, ngms_g_loc
+  INTEGER, ALLOCATABLE :: nls_loc(:)
+  INTEGER, ALLOCATABLE :: nlm_loc(:)
+  INTEGER, ALLOCATABLE :: nlsm_loc(:)
+
+  INTEGER :: ngm_exx, ngm_g_exx, gstart_exx
+  INTEGER, ALLOCATABLE :: ig_l2g_exx(:)
+  REAL(DP), ALLOCATABLE :: g_exx(:,:), gg_exx(:)
+  INTEGER, ALLOCATABLE :: mill_exx(:,:), nl_exx(:)
+  INTEGER :: ngms_exx, ngms_g_exx
+  INTEGER, ALLOCATABLE :: nls_exx(:)
+  INTEGER, ALLOCATABLE :: nlm_exx(:)
+  INTEGER, ALLOCATABLE :: nlsm_exx(:)
+
+  TYPE(fft_type_descriptor) :: dfftp_loc, dffts_loc
+  TYPE(fft_type_descriptor) :: dfftp_exx, dffts_exx
+  TYPE (sticks_map) :: smap_exx ! Stick map descriptor
+
+ CONTAINS
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE transform_evc_to_exx(type)
+  !-----------------------------------------------------------------------
+    !
+    USE wvfct,                ONLY : npwx, nbnd
+    USE io_files,             ONLY : nwordwfc, iunwfc, iunwfc_exx
+    USE klist,                ONLY : nks, ngk, igk_k
+    USE uspp,                 ONLY : nkb, vkb
+    USE wavefunctions_module, ONLY : evc
+    USE control_flags,        ONLY : io_level
+    USE buffers,              ONLY : open_buffer, get_buffer, save_buffer
+    USE mp_exx,               ONLY : max_ibands, negrp
+    !
+    !
+    IMPLICIT NONE
+    !
+    INTEGER, intent(in) :: type
+    INTEGER :: lda, n, ik
+    LOGICAL :: exst_mem, exst_file
+    !
+    IF (negrp.eq.1) THEN
+       !
+       ! no change in data structure is necessary
+       ! just copy all of the required data
+       !
+       ! get evc_exx
+       !
+       IF(.not.allocated(evc_exx))THEN
+          ALLOCATE(evc_exx(npwx*npol,nbnd))
+       END IF
+       evc_exx = evc
+       !
+       ! get igk_exx
+       !
+       IF(.not.allocated(igk_exx)) THEN
+          ALLOCATE( igk_exx( npwx, nks ) )
+          igk_exx = igk_k
+       END IF
+       !
+       ! get the wfc buffer is used
+       !
+       iunwfc_exx = iunwfc
+       nwordwfc_exx = nwordwfc
+       !
+       RETURN
+       !
+    END IF
+    !
+    ! change the data structure of evc and igk
+    !
+    lda = npwx
+    n = npwx 
+    npwx_local = npwx
+    IF( .not.allocated(ngk_local) ) allocate(ngk_local(nks))
+    ngk_local = ngk
+    !
+    IF ( .not.allocated(comm_recv) ) THEN
+       !
+       ! initialize all of the conversion maps and change the data structure
+       !
+       CALL initialize_local_to_exact_map(lda, nbnd)
+    ELSE
+       !
+       ! change the data structure
+       !
+       CALL change_data_structure(.TRUE.)
+    END IF
+    !
+    lda = npwx
+    n = npwx 
+    npwx_exx = npwx
+    IF( .not.allocated(ngk_exx) ) allocate(ngk_exx(nks))
+    ngk_exx = ngk
+    !
+    ! get evc_exx
+    !
+    IF(.not.allocated(evc_exx))THEN
+       ALLOCATE(evc_exx(lda*npol,max_ibands+2))
+       !
+       ! ... open files/buffer for wavefunctions (nwordwfc set in openfil)
+       ! ... io_level > 1 : open file, otherwise: open buffer
+       !
+       nwordwfc_exx  = size(evc_exx)
+       CALL open_buffer( iunwfc_exx, 'wfc_exx', nwordwfc_exx, io_level, &
+            exst_mem, exst_file )
+    END IF
+    !
+    DO ik=1, nks
+       !
+       ! read evc for the local data structure
+       !
+       IF ( nks > 1 ) CALL get_buffer(evc, nwordwfc, iunwfc, ik)
+       !
+       ! transform evc to the EXX data structure
+       !
+       CALL transform_to_exx(lda, n, nbnd, nbnd, ik, evc, evc_exx, type)
+       !
+       ! save evc to a buffer
+       !
+       IF ( nks > 1 ) CALL save_buffer ( evc_exx, nwordwfc_exx, iunwfc_exx, ik )
+    END DO
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE transform_evc_to_exx
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE transform_psi_to_exx(lda, n, m, psi)
+  !-----------------------------------------------------------------------
+    USE wvfct,        ONLY : current_k, npwx, nbnd
+    USE mp_exx,       ONLY : negrp, nibands, my_egrp_id, max_ibands
+    !
+    !
+    IMPLICIT NONE
+    !
+    Integer, INTENT(in) :: lda
+    INTEGER, INTENT(in) :: m
+    INTEGER, INTENT(inout) :: n
+    COMPLEX(DP), INTENT(in) :: psi(lda*npol,m) 
+    !
+    ! change to the EXX data strucutre
+    !
+    npwx_local = npwx
+    n_local = n
+    IF ( .not.allocated(comm_recv) ) THEN
+       !
+       ! initialize all of the conversion maps and change the data structure
+       !
+       CALL initialize_local_to_exact_map(lda, m)
+    ELSE
+       !
+       ! change the data structure
+       !
+       CALL change_data_structure(.TRUE.)
+    END IF
+    npwx_exx = npwx
+    n = ngk_exx(current_k)
+    !
+    ! get igk
+    !
+    CALL update_igk(.TRUE.)
+    !
+    ! get psi_exx
+    !
+    CALL transform_to_exx(lda, n, m, max_ibands, &
+         current_k, psi, psi_exx, 0)
+    !
+    ! zero hpsi_exx
+    !
+    hpsi_exx = 0.d0
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE transform_psi_to_exx
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE transform_hpsi_to_local(lda, n, m, hpsi)
+  !-----------------------------------------------------------------------
+    USE mp_exx,         ONLY : iexx_istart, iexx_iend, my_egrp_id
+    !
+    IMPLICIT NONE
+    !
+    INTEGER, INTENT(in) :: lda
+    INTEGER, INTENT(in) :: m
+    INTEGER, INTENT(inout) :: n
+    COMPLEX(DP), INTENT(out) :: hpsi(lda_original*npol,m)
+    INTEGER :: m_exx
+    !
+    ! change to the local data structure
+    !
+    CALL change_data_structure(.FALSE.)
+    !
+    ! get igk
+    !
+    CALL update_igk(.FALSE.)
+    n = n_local
+    !
+    ! transform hpsi_exx to the local data structure
+    !
+    m_exx = iexx_iend(my_egrp_id+1) - iexx_istart(my_egrp_id+1) + 1
+    CALL transform_to_local(m,m_exx,hpsi_exx,hpsi)
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE transform_hpsi_to_local
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE initialize_local_to_exact_map(lda, m)
+  !-----------------------------------------------------------------------
+    !
+    ! determine the mapping between the local and EXX data structures
+    !
+    USE wvfct,          ONLY : npwx, nbnd
+    USE klist,          ONLY : nks, igk_k
+    USE mp_exx,         ONLY : nproc_egrp, negrp, my_egrp_id, me_egrp, &
+                               intra_egrp_comm, inter_egrp_comm, &
+                               ibands, nibands, init_index_over_band, &
+                               iexx_istart, iexx_iend, max_ibands
+    USE mp_pools,       ONLY : nproc_pool, me_pool, intra_pool_comm
+    USE mp,             ONLY : mp_sum
+    USE gvect,          ONLY : ig_l2g
+    USE uspp,           ONLY : nkb
+    !
+    !
+    IMPLICIT NONE
+    !
+    Integer :: lda
+    INTEGER :: n, m
+    INTEGER, ALLOCATABLE :: local_map(:,:), exx_map(:,:)
+    INTEGER, ALLOCATABLE :: l2e_map(:,:), e2l_map(:,:,:)
+    INTEGER, ALLOCATABLE :: psi_source(:), psi_source_exx(:,:)
+    INTEGER :: current_index
+    INTEGER :: i, j, k, ik, im, ig, count, iproc, prev, iegrp
+    INTEGER :: total_lda(nks), prev_lda(nks)
+    INTEGER :: total_lda_exx(nks), prev_lda_exx(nks)
+    INTEGER :: n_local
+    INTEGER :: lda_max_local, lda_max_exx
+    INTEGER :: max_lda_egrp
+    INTEGER :: request_send(nproc_egrp), request_recv(nproc_egrp)
+    INTEGER :: ierr
+    INTEGER :: egrp_base, total_lda_egrp(nks), prev_lda_egrp(nks)
+    INTEGER :: igk_loc(npwx)
+    !
+    ! initialize the pair assignments
+    !
+    CALL init_index_over_band(inter_egrp_comm,nbnd,m)
+    !
+    ! allocate bookeeping arrays
+    !
+    IF ( .not.allocated(comm_recv) ) THEN
+       ALLOCATE(comm_recv(nproc_egrp,nks),comm_send(nproc_egrp,nks))
+    END IF
+    IF ( .not.allocated(lda_local) ) THEN
+       ALLOCATE(lda_local(nproc_pool,nks))
+       ALLOCATE(lda_exx(nproc_egrp,nks))
+    END IF
+    !
+    ! store the original values of lda and n
+    !
+    lda_original = lda
+    n_original = n
+    !
+    ! construct the local map
+    !
+    lda_local = 0
+    DO ik = 1, nks
+       igk_loc = igk_k(:,ik)
+       n = 0
+       DO i = 1, size(igk_loc)
+          IF(igk_loc(i).gt.0)n = n + 1
+       END DO
+       lda_local(me_pool+1,ik) = n
+       CALL mp_sum(lda_local(:,ik),intra_pool_comm)
+       total_lda(ik) = sum(lda_local(:,ik))
+       prev_lda(ik) = sum(lda_local(1:me_pool,ik))
+    END DO
+    ALLOCATE(local_map(maxval(total_lda),nks))
+    local_map = 0
+    DO ik = 1, nks
+       local_map(prev_lda(ik)+1:prev_lda(ik)+lda_local(me_pool+1,ik),ik) = &
+            ig_l2g(igk_k(1:lda_local(me_pool+1,ik),ik))
+    END DO
+    CALL mp_sum(local_map,intra_pool_comm)
+    !
+    !-----------------------------------------!
+    ! Switch to the exx data structure        !
+    !-----------------------------------------!
+    !
+    CALL change_data_structure(.TRUE.)
+    !
+    ! construct the exx map
+    !
+    lda_exx = 0
+    DO ik = 1, nks
+       n = 0
+       DO i = 1, size(igk_exx(:,ik))
+          IF(igk_exx(i,ik).gt.0)n = n + 1
+       END DO
+       lda_exx(me_egrp+1,ik) = n
+       CALL mp_sum(lda_exx(:,ik),intra_egrp_comm)
+       total_lda_exx(ik) = sum(lda_exx(:,ik))
+       prev_lda_exx(ik) = sum(lda_exx(1:me_egrp,ik))
+    END DO
+    ALLOCATE(exx_map(maxval(total_lda_exx),nks))
+    exx_map = 0
+    DO ik = 1, nks
+       exx_map(prev_lda_exx(ik)+1:prev_lda_exx(ik)+lda_exx(me_egrp+1,ik),ik) = &
+            ig_l2g(igk_exx(1:lda_exx(me_egrp+1,ik),ik))    
+    END DO
+    CALL mp_sum(exx_map,intra_egrp_comm)
+    !
+    ! construct the l2e_map
+    !
+    allocate( l2e_map(maxval(total_lda_exx),nks) )
+    l2e_map = 0
+    DO ik = 1, nks
+       DO ig = 1, lda_exx(me_egrp+1,ik)
+          DO j=1, total_lda(ik)
+             IF( local_map(j,ik).EQ.exx_map(ig+prev_lda_exx(ik),ik) ) exit
+          END DO
+          l2e_map(ig+prev_lda_exx(ik),ik) = j
+       END DO
+    END DO
+    CALL mp_sum(l2e_map,intra_egrp_comm)
+    !
+    ! plan communication for the data structure change
+    !
+    lda_max_local = maxval(lda_local)
+    lda_max_exx = maxval(lda_exx)
+    allocate(psi_source(maxval(total_lda_exx)))
+    !
+    DO ik = 1, nks
+       !
+       ! determine which task each value will come from
+       !
+       psi_source = 0
+       DO ig = 1, lda_exx(me_egrp+1,ik)
+          j = 1
+          DO i = 1, nproc_pool
+             j = j + lda_local(i,ik)
+             IF( j.gt.l2e_map(ig+prev_lda_exx(ik),ik) ) exit
+          END DO
+          psi_source(ig+prev_lda_exx(ik)) = i-1
+       END DO
+       CALL mp_sum(psi_source,intra_egrp_comm)
+       !
+       ! allocate communication packets to receive psi and hpsi
+       !
+       DO iproc=0, nproc_egrp-1
+          !
+          ! determine how many values need to come from iproc
+          !
+          count = 0
+          DO ig=1, lda_exx(me_egrp+1,ik)
+             IF ( MODULO(psi_source(ig+prev_lda_exx(ik)),nproc_egrp)&
+                  .eq.iproc ) THEN
+                count = count + 1
+             END IF
+          END DO
+          !
+          ! allocate the communication packet
+          !
+          comm_recv(iproc+1,ik)%size = count
+          IF (count.gt.0) THEN
+             IF (.not.ALLOCATED(comm_recv(iproc+1,ik)%msg)) THEN
+                ALLOCATE(comm_recv(iproc+1,ik)%indices(count))
+                ALLOCATE(comm_recv(iproc+1,ik)%msg(count,npol,max_ibands+2))
+             END IF
+          END IF
+          !
+          ! determine which values need to come from iproc
+          !
+          count = 0
+          DO ig=1, lda_exx(me_egrp+1,ik)
+             IF ( MODULO(psi_source(ig+prev_lda_exx(ik)),nproc_egrp)&
+                  .eq.iproc ) THEN
+                count = count + 1
+                comm_recv(iproc+1,ik)%indices(count) = ig
+             END IF
+          END DO
+          !
+       END DO
+       !
+       ! allocate communication packets to send psi and hpsi
+       !
+       prev = 0
+       DO iproc=0, nproc_egrp-1
+          !
+          ! determine how many values need to be sent to iproc
+          !
+          count = 0
+          DO ig=1, lda_exx(iproc+1,ik)
+             IF ( MODULO(psi_source(ig+prev),nproc_egrp).eq.me_egrp ) THEN
+                count = count + 1
+             END IF
+          END DO
+          !
+          ! allocate the communication packet
+          !
+          comm_send(iproc+1,ik)%size = count
+          IF (count.gt.0) THEN
+             IF (.not.ALLOCATED(comm_send(iproc+1,ik)%msg)) THEN
+                ALLOCATE(comm_send(iproc+1,ik)%indices(count))
+                ALLOCATE(comm_send(iproc+1,ik)%msg(count,npol,max_ibands+2))
+             END IF
+          END IF
+          !
+          ! determine which values need to be sent to iproc
+          !
+          count = 0
+          DO ig=1, lda_exx(iproc+1,ik)
+             IF ( MODULO(psi_source(ig+prev),nproc_egrp).eq.me_egrp ) THEN
+                count = count + 1
+                comm_send(iproc+1,ik)%indices(count) = l2e_map(ig+prev,ik)
+             END IF
+          END DO
+          !
+          prev = prev + lda_exx(iproc+1,ik)
+          !
+       END DO
+       !
+    END DO
+    !
+    ! allocate psi_exx and hpsi_exx
+    !
+    IF(allocated(psi_exx))DEALLOCATE(psi_exx)
+    ALLOCATE(psi_exx(npwx*npol, max_ibands ))
+    IF(allocated(hpsi_exx))DEALLOCATE(hpsi_exx)
+    ALLOCATE(hpsi_exx(npwx*npol, max_ibands ))
+    !
+    ! allocate communication arrays for the exx to local transformation
+    !
+    IF ( .not.allocated(comm_recv_reverse) ) THEN
+       ALLOCATE(comm_recv_reverse(nproc_egrp,nks))
+       ALLOCATE(comm_send_reverse(nproc_egrp,negrp,nks))
+    END IF
+    !
+    egrp_base = my_egrp_id*nproc_egrp
+    DO ik = 1, nks
+       total_lda_egrp(ik) = &
+            sum( lda_local(egrp_base+1:(egrp_base+nproc_egrp),ik) )
+       prev_lda_egrp(ik) = &
+            sum( lda_local(egrp_base+1:(egrp_base+me_egrp),ik) )
+    END DO
+    !
+    max_lda_egrp = 0
+    DO j = 1, negrp
+       DO ik = 1, nks
+          max_lda_egrp = max(max_lda_egrp, &
+               sum( lda_local((j-1)*nproc_egrp+1:j*nproc_egrp,ik) ) )
+       END DO
+    END DO
+    !
+    ! determine the e2l_map
+    !
+    allocate( e2l_map(max_lda_egrp,nks,negrp) )
+    e2l_map = 0
+    DO ik = 1, nks
+       DO ig = 1, lda_local(me_pool+1,ik)
+          DO j=1, total_lda_exx(ik)
+             IF( local_map(ig+prev_lda(ik),ik).EQ.exx_map(j,ik) ) exit
+          END DO
+          e2l_map(ig+prev_lda_egrp(ik),ik,my_egrp_id+1) = j
+       END DO
+    END DO
+    CALL mp_sum(e2l_map(:,:,my_egrp_id+1),intra_egrp_comm)
+    CALL mp_sum(e2l_map,inter_egrp_comm)
+    !
+    ! plan communication for the local to EXX data structure transformation
+    !
+    allocate(psi_source_exx( max_lda_egrp, negrp ))
+    DO ik = 1, nks
+       !
+       ! determine where each value is coming from
+       !
+       psi_source_exx = 0
+       DO ig = 1, lda_local(me_pool+1,ik)
+          j = 1
+          DO i = 1, nproc_egrp
+             j = j + lda_exx(i,ik)
+             IF( j.gt.e2l_map(ig+prev_lda_egrp(ik),ik,my_egrp_id+1) ) exit
+          END DO
+          psi_source_exx(ig+prev_lda_egrp(ik),my_egrp_id+1) = i-1
+       END DO
+       CALL mp_sum(psi_source_exx(:,my_egrp_id+1),intra_egrp_comm)
+       CALL mp_sum(psi_source_exx,inter_egrp_comm)
+       !
+       ! allocate communication packets to receive psi and hpsi (reverse)
+       !
+       DO iegrp=my_egrp_id+1, my_egrp_id+1
+          DO iproc=0, nproc_egrp-1
+             !
+             ! determine how many values need to come from iproc
+             !
+             count = 0
+             DO ig=1, lda_local(me_pool+1,ik)
+                IF ( psi_source_exx(ig+prev_lda_egrp(ik),iegrp).eq.iproc ) THEN
+                   count = count + 1
+                END IF
+             END DO
+             !
+             ! allocate the communication packet
+             !
+             comm_recv_reverse(iproc+1,ik)%size = count
+             IF (count.gt.0) THEN
+                IF (.not.ALLOCATED(comm_recv_reverse(iproc+1,ik)%msg)) THEN
+                   ALLOCATE(comm_recv_reverse(iproc+1,ik)%indices(count))
+                   ALLOCATE(comm_recv_reverse(iproc+1,ik)%msg(count,npol,m+2))
+                END IF
+             END IF
+             !
+             ! determine which values need to come from iproc
+             !
+             count = 0
+             DO ig=1, lda_local(me_pool+1,ik)
+                IF ( psi_source_exx(ig+prev_lda_egrp(ik),iegrp).eq.iproc ) THEN
+                   count = count + 1
+                   comm_recv_reverse(iproc+1,ik)%indices(count) = ig
+                END IF
+             END DO
+             
+          END DO
+       END DO
+       !
+       ! allocate communication packets to send psi and hpsi
+       !
+       DO iegrp=1, negrp
+          prev = 0
+          DO iproc=0, nproc_egrp-1
+             !
+             ! determine how many values need to be sent to iproc
+             !
+             count = 0
+             DO ig=1, lda_local(iproc+(iegrp-1)*nproc_egrp+1,ik)
+                IF ( psi_source_exx(ig+prev,iegrp).eq.me_egrp ) THEN
+                   count = count + 1
+                END IF
+             END DO
+             !
+             ! allocate the communication packet
+             !
+             comm_send_reverse(iproc+1,iegrp,ik)%size = count
+             IF (count.gt.0) THEN
+                IF (.not.ALLOCATED(comm_send_reverse(iproc+1,iegrp,ik)%msg))THEN
+                   ALLOCATE(comm_send_reverse(iproc+1,iegrp,ik)%indices(count))
+                   ALLOCATE(comm_send_reverse(iproc+1,iegrp,ik)%msg(count,npol,&
+                        iexx_iend(my_egrp_id+1)-iexx_istart(my_egrp_id+1)+3))
+                END IF
+             END IF
+             !
+             ! determine which values need to be sent to iproc
+             !
+             count = 0
+             DO ig=1, lda_local(iproc+(iegrp-1)*nproc_egrp+1,ik)
+                IF ( psi_source_exx(ig+prev,iegrp).eq.me_egrp ) THEN
+                   count = count + 1
+                   comm_send_reverse(iproc+1,iegrp,ik)%indices(count) = &
+                        e2l_map(ig+prev,ik,iegrp)
+                END IF
+             END DO
+             !
+             prev = prev + lda_local( (iegrp-1)*nproc_egrp+iproc+1, ik )
+             !
+          END DO
+       END DO
+       !
+    END DO
+    !
+    ! deallocate arrays
+    !
+    DEALLOCATE( local_map, exx_map )
+    DEALLOCATE( l2e_map, e2l_map )
+    DEALLOCATE( psi_source, psi_source_exx )
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE initialize_local_to_exact_map
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE transform_to_exx(lda, n, m, m_out, ik, psi, psi_out, type)
+  !-----------------------------------------------------------------------
+    !
+    ! transform psi into the EXX data structure, and place the result in psi_out
+    !
+    USE wvfct,        ONLY : nbnd
+    USE mp,           ONLY : mp_sum
+    USE mp_pools,     ONLY : nproc_pool, me_pool
+    USE mp_exx,       ONLY : intra_egrp_comm, inter_egrp_comm, &
+         nproc_egrp, me_egrp, negrp, my_egrp_id, nibands, ibands, &
+         max_ibands, all_start, all_end
+    USE parallel_include
+    !
+    !
+    IMPLICIT NONE
+    !
+    Integer :: lda
+    INTEGER :: n, m, m_out
+    COMPLEX(DP) :: psi(npwx_local*npol,m) 
+    COMPLEX(DP) :: psi_out(npwx_exx*npol,m_out)
+    INTEGER, INTENT(in) :: type
+
+    COMPLEX(DP), ALLOCATABLE :: psi_work(:,:,:,:), psi_gather(:,:)
+    INTEGER :: i, j, im, iproc, ig, ik, iegrp
+    INTEGER :: prev, lda_max_local
+
+    INTEGER :: request_send(nproc_egrp), request_recv(nproc_egrp)
+    INTEGER :: ierr
+    INTEGER :: current_ik
+    !INTEGER, EXTERNAL :: find_current_k
+    INTEGER :: recvcount(negrp)
+    INTEGER :: displs(negrp)
+#if defined(__MPI)
+    INTEGER :: istatus(MPI_STATUS_SIZE)
+#endif
+    INTEGER :: requests(max_ibands+2,negrp)
+    !
+    INTEGER :: ipol, my_lda, lda_offset, count
+    lda_max_local = maxval(lda_local)
+    current_ik = ik
+    !
+    !-------------------------------------------------------!
+    !Communication Part 1
+    !-------------------------------------------------------!
+    !
+    allocate(psi_work(lda_max_local,npol,m,negrp))
+    allocate(psi_gather(lda_max_local*npol,m))
+    DO im=1, m
+       my_lda = lda_local(me_pool+1,current_ik)
+       DO ipol=1, npol
+          lda_offset = lda_max_local*(ipol-1)
+          DO ig=1, my_lda
+             psi_gather(lda_offset+ig,im) = psi(npwx_local*(ipol-1)+ig,im)
+          END DO
+       END DO
+    END DO
+    recvcount = lda_max_local*npol
+    count = lda_max_local*npol
+#if defined (__MPI_NONBLOCKING)
+    IF ( type.eq.0 ) THEN
+       DO iegrp=1, negrp
+          displs(iegrp) = (iegrp-1)*(count*m)
+       END DO
+       DO iegrp=1, negrp
+          DO im=1, nibands(iegrp)
+             IF ( my_egrp_id.eq.(iegrp-1) ) THEN
+                DO j=1, negrp
+                   displs(j) = (j-1)*(count*m) + count*(ibands(im,iegrp)-1)
+                END DO
+             END IF
+#if defined(__MPI)
+             CALL MPI_IGATHERV( psi_gather(:, ibands(im,iegrp) ), &
+                  count, MPI_DOUBLE_COMPLEX, &
+                  psi_work, &
+                  recvcount, displs, MPI_DOUBLE_COMPLEX, &
+                  iegrp-1, &
+                  inter_egrp_comm, requests(im,iegrp), ierr )
+#endif
+          END DO
+       END DO
+
+    ELSE IF(type.eq.1) THEN
+#elif defined(__MPI)
+       CALL MPI_ALLGATHER( psi_gather, &
+            count*m, MPI_DOUBLE_COMPLEX, &
+            psi_work, &
+            count*m, MPI_DOUBLE_COMPLEX, &
+            inter_egrp_comm, ierr )
+#endif
+
+#if defined (__MPI_NONBLOCKING)
+    ELSE IF(type.eq.2) THEN !evc2
+
+       DO iegrp=1, negrp
+          displs(iegrp) = (iegrp-1)*(count*m)
+       END DO
+       DO iegrp=1, negrp
+          DO im=1, all_end(iegrp) - all_start(iegrp) + 1
+             !
+             IF(all_start(iegrp).eq.0) CYCLE
+             !
+             IF ( my_egrp_id.eq.(iegrp-1) ) THEN
+                DO j=1, negrp
+                   displs(j) = (j-1)*(count*m) + count*(im+all_start(iegrp)-2)
+                END DO
+             END IF
+#if defined(__MPI)
+             CALL MPI_IGATHERV( psi_gather(:, im+all_start(iegrp)-1 ), &
+                  count, MPI_DOUBLE_COMPLEX, &
+                  psi_work, &
+                  recvcount, displs, MPI_DOUBLE_COMPLEX, &
+                  iegrp-1, &
+                  inter_egrp_comm, requests(im,iegrp), ierr )
+#endif
+          END DO
+       END DO
+          
+    END IF
+    !
+    IF(type.eq.0)THEN
+       DO iegrp=1, negrp
+          DO im=1, nibands(iegrp)
+             CALL MPI_WAIT(requests(im,iegrp), istatus, ierr)
+          END DO
+       END DO
+    ELSEIF(type.eq.2)THEN
+       DO iegrp=1, negrp
+          DO im=1, all_end(iegrp) - all_start(iegrp) + 1
+             IF(all_start(iegrp).eq.0) CYCLE
+             CALL MPI_WAIT(requests(im,iegrp), istatus, ierr)
+          END DO
+       END DO
+    END IF
+#endif
+    !
+    !-------------------------------------------------------!
+    !Communication Part 2
+    !-------------------------------------------------------!
+    !
+    !send communication packets
+    !
+    DO iproc=0, nproc_egrp-1
+       IF ( comm_send(iproc+1,current_ik)%size.gt.0) THEN
+          DO i=1, comm_send(iproc+1,current_ik)%size
+             ig = comm_send(iproc+1,current_ik)%indices(i)
+             !
+             !determine which egrp this corresponds to
+             !
+             prev = 0
+             DO j=1, nproc_pool
+                IF ((prev+lda_local(j,current_ik)).ge.ig) THEN 
+                   ig = ig - prev
+                   exit
+                END IF
+                prev = prev + lda_local(j,current_ik)
+             END DO
+             !
+             ! prepare the message
+             !
+             DO ipol=1, npol
+             IF ( type.eq.0 ) THEN !psi or hpsi
+                DO im=1, nibands(my_egrp_id+1)
+                   comm_send(iproc+1,current_ik)%msg(i,ipol,im) = &
+                        psi_work(ig,ipol,ibands(im,my_egrp_id+1),1+(j-1)/nproc_egrp)
+                END DO
+             ELSE IF (type.eq.1) THEN !evc
+                DO im=1, m
+                   comm_send(iproc+1,current_ik)%msg(i,ipol,im) = &
+                        psi_work(ig,ipol,im,1+(j-1)/nproc_egrp)
+                END DO
+             ELSE IF ( type.eq.2 ) THEN !evc2
+                IF(all_start(my_egrp_id+1).gt.0) THEN
+                   DO im=1, all_end(my_egrp_id+1) - all_start(my_egrp_id+1) + 1
+                      comm_send(iproc+1,current_ik)%msg(i,ipol,im) = &
+                           psi_work(ig,ipol,im+all_start(my_egrp_id+1)-1,1+(j-1)/nproc_egrp)
+                   END DO
+                END IF
+             END IF
+             END DO
+             !
+          END DO
+          !
+          ! send the message
+          !
+#if defined(__MPI)
+          IF ( type.eq.0 ) THEN !psi or hpsi
+             CALL MPI_ISEND( comm_send(iproc+1,current_ik)%msg, &
+                  comm_send(iproc+1,current_ik)%size*npol*nibands(my_egrp_id+1), &
+                  MPI_DOUBLE_COMPLEX, &
+                  iproc, 100+iproc*nproc_egrp+me_egrp, &
+                  intra_egrp_comm, request_send(iproc+1), ierr )
+          ELSE IF (type.eq.1) THEN !evc
+             CALL MPI_ISEND( comm_send(iproc+1,current_ik)%msg, &
+                  comm_send(iproc+1,current_ik)%size*npol*m, MPI_DOUBLE_COMPLEX, &
+                  iproc, 100+iproc*nproc_egrp+me_egrp, &
+                  intra_egrp_comm, request_send(iproc+1), ierr )
+          ELSE IF (type.eq.2) THEN !evc2
+             CALL MPI_ISEND( comm_send(iproc+1,current_ik)%msg, &
+                  comm_send(iproc+1,current_ik)%size*npol*(all_end(my_egrp_id+1)-all_start(my_egrp_id+1)+1), &
+                  MPI_DOUBLE_COMPLEX, &
+                  iproc, 100+iproc*nproc_egrp+me_egrp, &
+                  intra_egrp_comm, request_send(iproc+1), ierr )
+          END IF
+#endif
+          !
+       END IF
+    END DO
+    !
+    ! begin receiving the messages
+    !
+    DO iproc=0, nproc_egrp-1
+       IF ( comm_recv(iproc+1,current_ik)%size.gt.0) THEN
+          !
+          ! receive the message
+          !
+#if defined(__MPI)
+          IF (type.eq.0) THEN !psi or hpsi
+             CALL MPI_IRECV( comm_recv(iproc+1,current_ik)%msg, &
+                  comm_recv(iproc+1,current_ik)%size*npol*nibands(my_egrp_id+1), &
+                  MPI_DOUBLE_COMPLEX, &
+                  iproc, 100+me_egrp*nproc_egrp+iproc, &
+                  intra_egrp_comm, request_recv(iproc+1), ierr )
+          ELSE IF (type.eq.1) THEN !evc
+             CALL MPI_IRECV( comm_recv(iproc+1,current_ik)%msg, &
+                  comm_recv(iproc+1,current_ik)%size*npol*m, MPI_DOUBLE_COMPLEX, &
+                  iproc, 100+me_egrp*nproc_egrp+iproc, &
+                  intra_egrp_comm, request_recv(iproc+1), ierr )
+          ELSE IF (type.eq.2) THEN !evc2
+             CALL MPI_IRECV( comm_recv(iproc+1,current_ik)%msg, &
+                  comm_recv(iproc+1,current_ik)%size*npol*(all_end(my_egrp_id+1)-all_start(my_egrp_id+1)+1), &
+                  MPI_DOUBLE_COMPLEX, &
+                  iproc, 100+me_egrp*nproc_egrp+iproc, &
+                  intra_egrp_comm, request_recv(iproc+1), ierr )
+          END IF
+#endif
+          !
+       END IF
+    END DO
+    !
+    ! assign psi_out
+    !
+    DO iproc=0, nproc_egrp-1
+       IF ( comm_recv(iproc+1,current_ik)%size.gt.0 ) THEN
+          !
+          ! wait for the message to be received
+          !
+#if defined(__MPI)
+          CALL MPI_WAIT(request_recv(iproc+1), istatus, ierr)
+#endif
+          !
+          DO i=1, comm_recv(iproc+1,current_ik)%size
+             ig = comm_recv(iproc+1,current_ik)%indices(i)
+             !
+             ! place the message into the correct elements of psi_out
+             !
+             IF (type.eq.0) THEN !psi or hpsi
+                DO im=1, nibands(my_egrp_id+1)
+                   DO ipol=1, npol
+                      psi_out(ig+npwx_exx*(ipol-1),im) = &
+                           comm_recv(iproc+1,current_ik)%msg(i,ipol,im)
+                   END DO
+                END DO
+             ELSE IF (type.eq.1) THEN !evc
+                DO im=1, m
+                   DO ipol=1, npol
+                      psi_out(ig+npwx_exx*(ipol-1),im) = &
+                           comm_recv(iproc+1,current_ik)%msg(i,ipol,im)
+                   END DO
+                END DO
+             ELSE IF (type.eq.2) THEN !evc2
+                DO im=1, all_end(my_egrp_id+1) - all_start(my_egrp_id+1) + 1
+                   DO ipol=1, npol
+                      psi_out(ig+npwx_exx*(ipol-1),im) = comm_recv(iproc+1,current_ik)%msg(i,ipol,im)
+                   END DO
+                END DO
+             END IF
+             !
+          END DO
+          !
+       END IF
+    END DO
+    !
+    ! wait for everything to finish sending
+    !
+#if defined(__MPI)
+    DO iproc=0, nproc_egrp-1
+       IF ( comm_send(iproc+1,current_ik)%size.gt.0 ) THEN
+          CALL MPI_WAIT(request_send(iproc+1), istatus, ierr)
+       END IF
+    END DO
+#endif
+    !
+    ! deallocate arrays
+    !
+    DEALLOCATE( psi_work, psi_gather )
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE transform_to_exx
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE change_data_structure(is_exx)
+  !-----------------------------------------------------------------------
+    !
+    ! change between the local and EXX data structures
+    ! is_exx = .TRUE. - change to the EXX data structure
+    ! is_exx = .FALSE. - change to the local data strucutre
+    !
+    USE cell_base,      ONLY : at, bg, tpiba2
+    USE cellmd,         ONLY : lmovecell
+    USE wvfct,          ONLY : npwx
+    USE gvect,          ONLY : gcutm, ig_l2g, g, gg, ngm, ngm_g, mill, &
+                               gstart, gvect_init, deallocate_gvect_exx
+    USE gvecs,          ONLY : gcutms, ngms, ngms_g, gvecs_init
+    USE gvecw,          ONLY : gkcut, ecutwfc, gcutw
+    USE klist,          ONLY : xk, nks, ngk
+    USE mp_bands,       ONLY : intra_bgrp_comm, ntask_groups, nyfft
+    USE mp_exx,         ONLY : intra_egrp_comm, me_egrp, exx_mode, nproc_egrp, &
+                               negrp, root_egrp
+    USE io_global,      ONLY : stdout
+    USE fft_base,       ONLY : dfftp, dffts, smap, fft_base_info
+    USE fft_types,      ONLY : fft_type_init
+    USE recvec_subs,    ONLY : ggen, ggens
+    !
+    IMPLICIT NONE
+    !
+    LOGICAL, intent(in) :: is_exx
+    INTEGER, EXTERNAL  :: n_plane_waves
+    COMPLEX(DP), ALLOCATABLE :: work_space(:)
+    INTEGER :: ik, i
+    INTEGER :: ngm_, ngs_, ngw_
+    LOGICAL exst
+#if defined (__MPI)
+  LOGICAL :: lpara = .true.
+#else
+  LOGICAL :: lpara = .false.
+#endif
+    !
+    IF (negrp.eq.1) RETURN
+    !
+    IF (first_data_structure_change) THEN
+       allocate( ig_l2g_loc(ngm), g_loc(3,ngm), gg_loc(ngm) )
+       allocate( mill_loc(3,ngm), nl_loc(ngm) )
+       allocate( nls_loc(size(dffts%nl)) )
+       IF ( gamma_only) THEN
+          allocate( nlm_loc(size(dfftp%nlm)) )
+          allocate( nlsm_loc(size(dffts%nlm)) )
+       END IF
+       ig_l2g_loc = ig_l2g
+       g_loc = g
+       gg_loc = gg
+       mill_loc = mill
+       nl_loc = dfftp%nl
+       nls_loc = dffts%nl
+       IF ( gamma_only) THEN
+          nlm_loc = dfftp%nlm
+          nlsm_loc = dffts%nlm
+       END IF
+       ngm_loc = ngm
+       ngm_g_loc = ngm_g
+       gstart_loc = gstart
+       ngms_loc = ngms
+       ngms_g_loc = ngms_g
+    END IF
+    !
+    ! generate the gvectors for the new data structure
+    !
+    IF (is_exx) THEN
+       exx_mode = 1
+       IF(first_data_structure_change)THEN
+          dfftp_loc = dfftp
+          dffts_loc = dffts
+
+          CALL fft_type_init( dffts_exx, smap_exx, "wave", gamma_only, &
+               lpara, intra_egrp_comm, at, bg, gkcut, gcutms/gkcut, &
+               nyfft=ntask_groups )
+          CALL fft_type_init( dfftp_exx, smap_exx, "rho", gamma_only, &
+               lpara, intra_egrp_comm, at, bg,  gcutm, nyfft=nyfft )
+          CALL fft_base_info( ionode, stdout )
+          ngs_ = dffts_exx%ngl( dffts_exx%mype + 1 )
+          ngm_ = dfftp_exx%ngl( dfftp_exx%mype + 1 )
+          IF( gamma_only ) THEN
+             ngs_ = (ngs_ + 1)/2
+             ngm_ = (ngm_ + 1)/2
+          END IF
+          dfftp = dfftp_exx
+          dffts = dffts_exx
+          ngm = ngm_
+          ngms = ngs_
+       ELSE
+          dfftp = dfftp_exx
+          dffts = dffts_exx
+          ngm = ngm_exx
+          ngms = ngms_exx
+       END IF
+       call deallocate_gvect_exx()
+       call gvect_init( ngm , intra_egrp_comm )
+       call gvecs_init( ngms , intra_egrp_comm )
+    ELSE
+       exx_mode = 2
+       dfftp = dfftp_loc
+       dffts = dffts_loc
+       ngm = ngm_loc
+       ngms = ngms_loc
+       call deallocate_gvect_exx()
+       call gvect_init( ngm , intra_bgrp_comm )
+       call gvecs_init( ngms , intra_bgrp_comm )
+       exx_mode = 0
+    END IF
+    !
+    IF (first_data_structure_change) THEN
+       CALL ggen ( dfftp, gamma_only, at, bg, gcutm, ngm_g, ngm, &
+            g, gg, mill, ig_l2g, gstart )
+       CALL ggens( dffts, gamma_only, at, g, gg, mill, gcutms, ngms )
+       allocate( ig_l2g_exx(ngm), g_exx(3,ngm), gg_exx(ngm) )
+       allocate( mill_exx(3,ngm), nl_exx(ngm) )
+       allocate( nls_exx(size(dffts%nl)) )
+       allocate( nlm_exx(size(dfftp%nlm) ) )
+       allocate( nlsm_exx(size(dffts%nlm) ) )
+       ig_l2g_exx = ig_l2g
+       g_exx = g
+       gg_exx = gg
+       mill_exx = mill
+       nl_exx = dfftp%nl
+       nls_exx = dffts%nl
+       IF( gamma_only ) THEN
+          nlm_exx = dfftp%nlm
+          nlsm_exx = dffts%nlm
+       END IF
+       ngm_exx = ngm
+       ngm_g_exx = ngm_g
+       gstart_exx = gstart
+       ngms_exx = ngms
+       ngms_g_exx = ngms_g
+    ELSE IF ( is_exx ) THEN
+       ig_l2g = ig_l2g_exx
+       g = g_exx
+       gg = gg_exx
+       mill = mill_exx
+       ! workaround: here dfft?%nl* are unallocated
+       ! some compilers go on and allocate, some others crash
+       IF ( .NOT. ALLOCATED(dfftp%nl) ) ALLOCATE (dfftp%nl(size(nl_exx)))
+       IF ( .NOT. ALLOCATED(dffts%nl) ) ALLOCATE (dffts%nl(size(nls_exx)))
+       IF ( gamma_only .AND. .NOT.ALLOCATED(dfftp%nlm) ) ALLOCATE (dfftp%nlm(size(nlm_exx)))
+       IF ( gamma_only .AND. .NOT.ALLOCATED(dffts%nlm) ) ALLOCATE (dffts%nlm(size(nlsm_exx)))
+       ! end workaround. FIXME: this part of code must disappear ASAP
+       dfftp%nl = nl_exx
+       dffts%nl = nls_exx
+       IF( gamma_only ) THEN
+          dfftp%nlm = nlm_exx
+          dffts%nlm = nlsm_exx
+       ENDIF
+       ngm = ngm_exx
+       ngm_g = ngm_g_exx
+       gstart = gstart_exx
+       ngms = ngms_exx
+       ngms_g = ngms_g_exx
+    ELSE ! not is_exx
+       ig_l2g = ig_l2g_loc
+       g = g_loc
+       gg = gg_loc
+       mill = mill_loc
+       dfftp%nl = nl_loc
+       dffts%nl = nls_loc
+       IF( gamma_only ) THEN
+          dfftp%nlm = nlm_loc
+          dffts%nlm = nlsm_loc
+       END IF
+       ngm = ngm_loc
+       ngm_g = ngm_g_loc
+       gstart = gstart_loc
+       ngms = ngms_loc
+       ngms_g = ngms_g_loc
+    END IF
+    !
+    ! get npwx and ngk
+    !
+    IF ( is_exx.and.npwx_exx.gt.0 ) THEN
+       npwx = npwx_exx
+       ngk = ngk_exx
+    ELSE IF ( .not.is_exx.and.npwx_local.gt.0 ) THEN
+       npwx = npwx_local
+       ngk = ngk_local
+    ELSE
+       npwx = n_plane_waves (gcutw, nks, xk, g, ngm)
+    END IF
+    !
+    ! get igk
+    !
+    IF( first_data_structure_change ) THEN
+       allocate(igk_exx(npwx,nks),work_space(npwx))
+       first_data_structure_change = .FALSE.
+       IF ( nks.eq.1 ) THEN
+          CALL gk_sort( xk, ngm, g, ecutwfc / tpiba2, ngk, igk_exx, work_space )
+       END IF
+       IF ( nks > 1 ) THEN
+          !
+          DO ik = 1, nks
+             CALL gk_sort( xk(1,ik), ngm, g, ecutwfc / tpiba2, ngk(ik), &
+                  igk_exx(1,ik), work_space )
+          END DO
+          !
+       END IF
+       DEALLOCATE( work_space )
+    END IF
+    !
+    ! generate ngl and igtongl
+    !
+    CALL gshells( lmovecell )
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE change_data_structure
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE update_igk(is_exx)
+  !-----------------------------------------------------------------------
+    USE cell_base,      ONLY : tpiba2
+    USE gvect,          ONLY : ngm, g
+    USE gvecw,          ONLY : ecutwfc
+    USE wvfct,          ONLY : npwx, current_k
+    USE klist,          ONLY : xk, igk_k
+    USE mp_exx,         ONLY : negrp
+    !
+    !
+    IMPLICIT NONE
+    !
+    LOGICAL, intent(in) :: is_exx
+    COMPLEX(DP), ALLOCATABLE :: work_space(:)
+    INTEGER :: comm
+    INTEGER :: npw, ik, i
+    LOGICAL exst
+    !
+    IF (negrp.eq.1) RETURN
+    !
+    ! get igk
+    !
+    allocate(work_space(npwx))
+    ik = current_k
+    IF(is_exx) THEN
+       CALL gk_sort( xk(1,ik), ngm, g, ecutwfc / tpiba2, npw, igk_exx(1,ik), &
+            work_space )
+    ELSE
+       CALL gk_sort( xk(1,ik), ngm, g, ecutwfc / tpiba2, npw, igk_k(1,ik), &
+            work_space )
+    END IF
+    !
+    DEALLOCATE( work_space )
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE update_igk
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE result_sum (n, m, data)
+  !-----------------------------------------------------------------------
+    USE parallel_include
+    USE mp_exx,       ONLY : iexx_start, iexx_end, inter_egrp_comm, &
+                               intra_egrp_comm, my_egrp_id, negrp, &
+                               max_pairs, egrp_pairs, max_contributors, &
+                               contributed_bands, all_end, &
+                               iexx_istart, iexx_iend, band_roots
+    USE mp,           ONLY : mp_sum, mp_bcast
+
+    INTEGER, INTENT(in) :: n, m
+    COMPLEX(DP), INTENT(inout) :: data(n,m)
+#if defined(__MPI)
+    INTEGER :: istatus(MPI_STATUS_SIZE)
+    COMPLEX(DP), ALLOCATABLE :: recvbuf(:,:)
+    COMPLEX(DP) :: data_sum(n,m), test(negrp)
+    INTEGER :: im, iegrp, ibuf, i, j, nsending(m)
+    INTEGER :: ncontributing(m)
+    INTEGER :: contrib_this(negrp,m), displs(negrp,m)
+
+    INTEGER sendcount, sendtype, ierr, root, request(m)
+    INTEGER sendc(negrp), sendd(negrp)
+#endif
+    !
+    IF (negrp.eq.1) RETURN
+    !
+#if defined(__MPI)
+    ! gather data onto the correct nodes
+    !
+    ALLOCATE( recvbuf( n*max_contributors, max(1,iexx_end-iexx_start+1) ) )
+    displs = 0
+    ibuf = 0
+    nsending = 0
+    contrib_this = 0
+    !
+    DO im=1, m
+       !
+       IF(contributed_bands(im,my_egrp_id+1)) THEN
+          sendcount = n
+       ELSE
+          sendcount = 0
+       END IF
+       !
+       root = band_roots(im)
+       !
+       IF(my_egrp_id.eq.root) THEN
+          !
+          ! determine the number of sending processors
+          !
+          ibuf = ibuf + 1
+          ncontributing(im) = 0
+          DO iegrp=1, negrp
+             IF(contributed_bands(im,iegrp)) THEN
+                ncontributing(im) = ncontributing(im) + 1
+                contrib_this(iegrp,im) = n
+                IF(iegrp.lt.negrp) displs(iegrp+1,im) = displs(iegrp,im) + n
+                nsending(im) = nsending(im) + 1
+             ELSE
+                contrib_this(iegrp,im) = 0
+                IF(iegrp.lt.negrp) displs(iegrp+1,im) = displs(iegrp,im)
+             END IF
+          END DO
+       END IF
+       !
+#if defined(__MPI_NONBLOCKING)
+       CALL MPI_IGATHERV(data(:,im), sendcount, MPI_DOUBLE_COMPLEX, &
+            recvbuf(:,max(1,ibuf)), contrib_this(:,im), &
+            displs(:,im), MPI_DOUBLE_COMPLEX, &
+            root, inter_egrp_comm, request(im), ierr)
+#else
+       CALL MPI_GATHERV(data(:,im), sendcount, MPI_DOUBLE_COMPLEX, &
+            recvbuf(:,max(1,ibuf)), contrib_this(:,im), &
+            displs(:,im), MPI_DOUBLE_COMPLEX, &
+            root, inter_egrp_comm, ierr)
+#endif
+       !
+    END DO
+    !
+#if defined(__MPI_NONBLOCKING)
+    DO im=1, m
+       CALL MPI_WAIT(request(im), istatus, ierr)
+    END DO
+#endif
+    !
+    ! perform the sum
+    !
+    DO im=iexx_istart(my_egrp_id+1), iexx_iend(my_egrp_id+1)
+       IF(im.eq.0)exit
+       data(:,im) = 0._dp
+       ibuf = im - iexx_istart(my_egrp_id+1) + 1
+       DO j=1, nsending(im)
+          DO i=1, n
+             data(i,im) = data(i,im) + recvbuf(i+n*(j-1),ibuf)
+          END DO
+       END DO
+    END DO
+#endif
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE result_sum
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE transform_to_local(m, m_exx, psi, psi_out)
+  !-----------------------------------------------------------------------
+    USE mp,           ONLY : mp_sum
+    USE mp_pools,     ONLY : nproc_pool, me_pool, intra_pool_comm
+    USE mp_exx,       ONLY : intra_egrp_comm, inter_egrp_comm, &
+         nproc_egrp, me_egrp, negrp, my_egrp_id, iexx_istart, iexx_iend
+    USE parallel_include
+    USE wvfct,        ONLY : current_k
+    !
+    !
+    IMPLICIT NONE
+    !
+    INTEGER :: m, m_exx
+    COMPLEX(DP) :: psi(npwx_exx*npol,m_exx)
+    COMPLEX(DP) :: psi_out(npwx_local*npol,m)
+    !
+    INTEGER :: i, j, im, iproc, ig, ik, current_ik, iegrp
+    INTEGER :: prev, lda_max_local, prev_lda_exx
+    INTEGER :: my_bands, recv_bands, tag
+    !
+    INTEGER :: request_send(nproc_egrp,negrp), request_recv(nproc_egrp,negrp)
+    INTEGER :: ierr
+    INTEGER :: ipol
+#if defined(__MPI)
+    INTEGER :: istatus(MPI_STATUS_SIZE)
+#endif
+    !INTEGER, EXTERNAL :: find_current_k
+    !
+    current_ik = current_k
+    prev_lda_exx = sum( lda_exx(1:me_egrp,current_ik) )
+    !
+    my_bands = iexx_iend(my_egrp_id+1) - iexx_istart(my_egrp_id+1) + 1
+    !
+    ! send communication packets
+    !
+    IF ( iexx_istart(my_egrp_id+1).gt.0 ) THEN
+       DO iegrp=1, negrp
+          DO iproc=0, nproc_egrp-1
+             IF ( comm_send_reverse(iproc+1,iegrp,current_ik)%size.gt.0) THEN
+                DO i=1, comm_send_reverse(iproc+1,iegrp,current_ik)%size
+                   ig = comm_send_reverse(iproc+1,iegrp,current_ik)%indices(i)
+                   ig = ig - prev_lda_exx
+                   !
+                   DO im=1, my_bands
+                      DO ipol=1, npol
+                         comm_send_reverse(iproc+1,iegrp,current_ik)%msg(i,ipol,im) = &
+                              psi(ig+npwx_exx*(ipol-1),im)
+                      END DO
+                   END DO
+                   !
+                END DO
+                !
+                ! send the message
+                !
+                tag = 0
+#if defined(__MPI)
+                CALL MPI_ISEND( comm_send_reverse(iproc+1,iegrp,current_ik)%msg, &
+                     comm_send_reverse(iproc+1,iegrp,current_ik)%size*npol*my_bands, &
+                     MPI_DOUBLE_COMPLEX, &
+                     iproc+(iegrp-1)*nproc_egrp, &
+                     tag, &
+                     intra_pool_comm, request_send(iproc+1,iegrp), ierr )
+#endif
+                !
+             END IF
+          END DO
+       END DO
+    END IF
+    !
+    ! begin receiving the communication packets
+    !
+    DO iegrp=1, negrp
+       !
+       IF ( iexx_istart(iegrp).le.0 ) CYCLE
+       !
+       recv_bands = iexx_iend(iegrp) - iexx_istart(iegrp) + 1
+       !
+       DO iproc=0, nproc_egrp-1
+          IF ( comm_recv_reverse(iproc+1,current_ik)%size.gt.0) THEN
+             !
+             !receive the message
+             !
+             tag = 0
+#if defined(__MPI)
+             CALL MPI_IRECV( comm_recv_reverse(iproc+1,current_ik)%msg(:,:,iexx_istart(iegrp)), &
+                  comm_recv_reverse(iproc+1,current_ik)%size*npol*recv_bands, &
+                  MPI_DOUBLE_COMPLEX, &
+                  iproc+(iegrp-1)*nproc_egrp, &
+                  tag, &
+                  intra_pool_comm, request_recv(iproc+1,iegrp), ierr )
+#endif
+             !
+          END IF
+       END DO
+    END DO
+    !
+    ! assign psi
+    !
+    DO iproc=0, nproc_egrp-1
+       IF ( comm_recv_reverse(iproc+1,current_ik)%size.gt.0 ) THEN
+          !
+#if defined(__MPI)
+          DO iegrp=1, negrp
+             IF ( iexx_istart(iegrp).le.0 ) CYCLE
+             CALL MPI_WAIT(request_recv(iproc+1,iegrp), istatus, ierr)
+          END DO
+#endif
+          !
+          DO i=1, comm_recv_reverse(iproc+1,current_ik)%size
+             ig = comm_recv_reverse(iproc+1,current_ik)%indices(i)
+             !
+             ! set psi_out
+             !
+             DO im=1, m
+                DO ipol=1, npol
+                   psi_out(ig+npwx_local*(ipol-1),im) = psi_out(ig+npwx_local*(ipol-1),im) + &
+                        comm_recv_reverse(iproc+1,current_ik)%msg(i,ipol,im)
+                END DO
+             END DO
+             !
+          END DO
+          !
+       END IF
+    END DO
+    !
+    ! wait for everything to finish sending
+    !
+#if defined(__MPI)
+    IF ( iexx_istart(my_egrp_id+1).gt.0 ) THEN
+       DO iproc=0, nproc_egrp-1
+          DO iegrp=1, negrp
+             IF ( comm_send_reverse(iproc+1,iegrp,current_ik)%size.gt.0 ) THEN
+                CALL MPI_WAIT(request_send(iproc+1,iegrp), istatus, ierr)
+             END IF
+          END DO
+       END DO
+    END IF
+#endif
+    !
+    !-----------------------------------------------------------------------
+  END SUBROUTINE transform_to_local
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE exxbuff_comm(exxbuff,exxtemp,ikq,lda,jstart,jend)
+  !-----------------------------------------------------------------------
+    USE mp_exx,               ONLY : my_egrp_id, inter_egrp_comm, jblock, &
+                                     all_end, negrp
+    USE mp,             ONLY : mp_bcast
+    USE parallel_include
+    COMPLEX(DP), intent(in)    :: exxbuff(:,:,:)
+    COMPLEX(DP), intent(inout) :: exxtemp(lda,jend-jstart+1)
+    INTEGER, intent(in) :: ikq, lda, jstart, jend
+    INTEGER :: jbnd, iegrp, ierr, request_exxbuff(jend-jstart+1)
+#if defined(__MPI)
+    INTEGER :: istatus(MPI_STATUS_SIZE)
+#endif
+
+    DO jbnd=jstart, jend
+       !determine which band group has this value of exxbuff
+       DO iegrp=1, negrp
+          IF(all_end(iegrp) >= jbnd) exit
+       END DO
+
+       IF (iegrp == my_egrp_id+1) THEN
+          exxtemp(:,jbnd-jstart+1) = exxbuff(:,jbnd,ikq)
+       END IF
+
+#if defined(__MPI_NONBLOCKING)
+       CALL MPI_IBCAST(exxtemp(:,jbnd-jstart+1), &
+            lda, &
+            MPI_DOUBLE_COMPLEX, &
+            iegrp-1, &
+            inter_egrp_comm, &
+            request_exxbuff(jbnd-jstart+1), ierr)
+#elif defined(__MPI)
+       CALL mp_bcast(exxtemp(:,jbnd-jstart+1),iegrp-1,inter_egrp_comm)
+#endif
+    END DO
+
+    DO jbnd=jstart, jend
+#if defined(__MPI_NONBLOCKING)
+       CALL MPI_WAIT(request_exxbuff(jbnd-jstart+1), istatus, ierr)
+#endif
+    END DO
+
+  !
+  !-----------------------------------------------------------------------
+  END SUBROUTINE exxbuff_comm
+  !-----------------------------------------------------------------------
+  !
+  !-----------------------------------------------------------------------
+  SUBROUTINE exxbuff_comm_gamma(exxbuff,exxtemp,ikq,lda,jstart,jend,jlength)
+  !-----------------------------------------------------------------------
+    USE mp_exx,               ONLY : my_egrp_id, inter_egrp_comm, jblock, &
+                                     all_end, negrp
+    USE mp,             ONLY : mp_bcast
+    USE parallel_include
+    COMPLEX(DP), intent(in)    :: exxbuff(:,:,:)
+    COMPLEX(DP), intent(inout) :: exxtemp(lda*npol,jlength)
+    INTEGER, intent(in) :: ikq, lda, jstart, jend, jlength
+    INTEGER :: jbnd, iegrp, ierr, request_exxbuff(jend-jstart+1), ir
+#if defined(__MPI)
+    INTEGER :: istatus(MPI_STATUS_SIZE)
+#endif
+    REAL(DP), ALLOCATABLE :: work(:,:)
+
+    CALL start_clock ('comm_buff')
+
+    ALLOCATE ( work(lda*npol,jend-jstart+1) )
+    DO jbnd=jstart, jend
+       !determine which band group has this value of exxbuff
+       DO iegrp=1, negrp
+          IF(all_end(iegrp) >= jbnd) exit
+       END DO
+
+       IF (iegrp == my_egrp_id+1) THEN
+!          exxtemp(:,jbnd-jstart+1) = exxbuff(:,jbnd,ikq)
+          IF( MOD(jbnd,2) == 1 ) THEN
+             work(:,jbnd-jstart+1) = REAL(exxbuff(:,jbnd/2+1,ikq))
+          ELSE
+             work(:,jbnd-jstart+1) = AIMAG(exxbuff(:,jbnd/2,ikq))
+          END IF
+       END IF
+
+#if defined(__MPI_NONBLOCKING)
+       CALL MPI_IBCAST(work(:,jbnd-jstart+1), &
+            lda*npol, &
+            MPI_DOUBLE_PRECISION, &
+            iegrp-1, &
+            inter_egrp_comm, &
+            request_exxbuff(jbnd-jstart+1), ierr)
+#elif defined(__MPI)
+       CALL mp_bcast(work(:,jbnd-jstart+1),iegrp-1,inter_egrp_comm)
+#endif
+    END DO
+
+    DO jbnd=jstart, jend
+#if defined(__MPI_NONBLOCKING)
+       CALL MPI_WAIT(request_exxbuff(jbnd-jstart+1), istatus, ierr)
+#endif
+    END DO
+    DO jbnd=jstart, jend, 2
+       IF (jbnd < jend) THEN
+          ! two real bands can be coupled into a single complex one
+          DO ir=1, lda*npol
+             exxtemp(ir,1+(jbnd-jstart+1)/2) = CMPLX( work(ir,jbnd-jstart+1),&
+                                                      work(ir,jbnd-jstart+2),&
+                                                      KIND=dp )
+          END DO
+       ELSE
+          ! case of lone last band
+          DO ir=1, lda*npol
+             exxtemp(ir,1+(jbnd-jstart+1)/2) = CMPLX( work(ir,jbnd-jstart+1),&
+                                                      0.0_dp, KIND=dp )
+          END DO
+       ENDIF
+    END DO
+    DEALLOCATE ( work )
+
+    CALL stop_clock ('comm_buff')
+  !
+  !-----------------------------------------------------------------------
+  END SUBROUTINE exxbuff_comm_gamma
+  !-----------------------------------------------------------------------
+
+END MODULE exx_band
+!-----------------------------------------------------------------------
diff --git a/PW/src/make.depend b/PW/src/make.depend
index e1efc68bc..f8c6a50fe 100644
--- a/PW/src/make.depend
+++ b/PW/src/make.depend
@@ -493,14 +493,35 @@ exx.o : ../../Modules/splinelib.o
 exx.o : ../../Modules/uspp.o
 exx.o : ../../Modules/wavefunctions.o
 exx.o : ../../UtilXlib/mp.o
-exx.o : ../../UtilXlib/parallel_include.o
 exx.o : buffers.o
+exx.o : exx_band.o
 exx.o : exx_base.o
 exx.o : paw_exx.o
 exx.o : pwcom.o
 exx.o : realus.o
 exx.o : symm_base.o
 exx.o : us_exx.o
+exx_band.o : ../../FFTXlib/fft_types.o
+exx_band.o : ../../FFTXlib/stick_base.o
+exx_band.o : ../../Modules/cell_base.o
+exx_band.o : ../../Modules/control_flags.o
+exx_band.o : ../../Modules/fft_base.o
+exx_band.o : ../../Modules/gvecw.o
+exx_band.o : ../../Modules/io_files.o
+exx_band.o : ../../Modules/io_global.o
+exx_band.o : ../../Modules/kind.o
+exx_band.o : ../../Modules/mp_bands.o
+exx_band.o : ../../Modules/mp_exx.o
+exx_band.o : ../../Modules/mp_pools.o
+exx_band.o : ../../Modules/noncol.o
+exx_band.o : ../../Modules/recvec.o
+exx_band.o : ../../Modules/recvec_subs.o
+exx_band.o : ../../Modules/uspp.o
+exx_band.o : ../../Modules/wavefunctions.o
+exx_band.o : ../../UtilXlib/mp.o
+exx_band.o : ../../UtilXlib/parallel_include.o
+exx_band.o : buffers.o
+exx_band.o : pwcom.o
 exx_base.o : ../../FFTXlib/fft_types.o
 exx_base.o : ../../FFTXlib/stick_base.o
 exx_base.o : ../../Modules/cell_base.o
@@ -964,6 +985,7 @@ input.o : dynamics_module.o
 input.o : esm.o
 input.o : extfield.o
 input.o : exx.o
+input.o : exx_base.o
 input.o : ldaU.o
 input.o : loc_scdm.o
 input.o : martyna_tuckerman.o
@@ -1018,6 +1040,7 @@ loc_scdm.o : ../../Modules/mp_bands.o
 loc_scdm.o : ../../Modules/noncol.o
 loc_scdm.o : ../../UtilXlib/mp.o
 loc_scdm.o : exx.o
+loc_scdm.o : exx_base.o
 loc_scdm.o : pwcom.o
 loc_scdm.o : scf_mod.o
 make_pointlists.o : ../../Modules/cell_base.o
@@ -1082,6 +1105,7 @@ memory_report.o : ../../Modules/uspp.o
 memory_report.o : ../../Modules/wannier_new.o
 memory_report.o : atomic_wfc_mod.o
 memory_report.o : exx.o
+memory_report.o : exx_base.o
 memory_report.o : ldaU.o
 memory_report.o : pwcom.o
 mix_rho.o : ../../FFTXlib/fft_interfaces.o
@@ -1576,6 +1600,7 @@ pw_restart_new.o : bp_mod.o
 pw_restart_new.o : buffers.o
 pw_restart_new.o : extfield.o
 pw_restart_new.o : exx.o
+pw_restart_new.o : exx_base.o
 pw_restart_new.o : io_rho_xml.o
 pw_restart_new.o : ldaU.o
 pw_restart_new.o : pwcom.o
@@ -1872,6 +1897,7 @@ setup.o : atomic_wfc_mod.o
 setup.o : bp_mod.o
 setup.o : extfield.o
 setup.o : exx.o
+setup.o : exx_base.o
 setup.o : ldaU.o
 setup.o : pw_restart.o
 setup.o : pw_restart_new.o
diff --git a/TDDFPT/src/make.depend b/TDDFPT/src/make.depend
index b9ee8a5b3..345c9a531 100644
--- a/TDDFPT/src/make.depend
+++ b/TDDFPT/src/make.depend
@@ -293,6 +293,7 @@ lr_exx_kernel.o : ../../Modules/mp_global.o
 lr_exx_kernel.o : ../../Modules/recvec.o
 lr_exx_kernel.o : ../../Modules/wavefunctions.o
 lr_exx_kernel.o : ../../PW/src/exx.o
+lr_exx_kernel.o : ../../PW/src/exx_base.o
 lr_exx_kernel.o : ../../PW/src/pwcom.o
 lr_exx_kernel.o : ../../PW/src/realus.o
 lr_exx_kernel.o : ../../PW/src/symm_base.o
@@ -401,7 +402,6 @@ lr_read_wf.o : ../../Modules/recvec.o
 lr_read_wf.o : ../../Modules/uspp.o
 lr_read_wf.o : ../../Modules/wavefunctions.o
 lr_read_wf.o : ../../PW/src/buffers.o
-lr_read_wf.o : ../../PW/src/exx.o
 lr_read_wf.o : ../../PW/src/pwcom.o
 lr_read_wf.o : ../../PW/src/realus.o
 lr_read_wf.o : lr_exx_kernel.o