When restarting an EXX calculation the code did not keep track of whether the EXX operator was being applied or not.

Hence on restart both the LDA exchange and EXX operators were applied. The status of the EXX operator is now writen to data-file.xml and restart handeled properly. Thanks to SdG.

git-svn-id: http://qeforge.qe-forge.org/svn/q-e/trunk/espresso@8118 c92efa57-630b-4861-b058-cf58834340f0

Modules/xml_io_base.f90

@@ -1291,10 +1291,10 @@ MODULE xml_io_base
     !------------------------------------------------------------------------
     SUBROUTINE write_exx( x_gamma_extrapolation, nqx1, nqx2, nqx3, &
                           exxdiv_treatment, yukawa, ecutvcut, exx_fraction, &
-                          screening_parameter )
+                          screening_parameter, exx_is_active )
       !------------------------------------------------------------------------
       !
-      LOGICAL,            INTENT(IN) :: x_gamma_extrapolation
+      LOGICAL,            INTENT(IN) :: x_gamma_extrapolation, exx_is_active
       INTEGER,  OPTIONAL, INTENT(IN) :: nqx1, nqx2, nqx3
       CHARACTER(LEN=*),   INTENT(IN) :: exxdiv_treatment
       REAL(DP),           INTENT(IN) :: yukawa, ecutvcut, exx_fraction
@@ -1310,6 +1310,7 @@ MODULE xml_io_base
       call iotk_write_dat(iunpun, "ecutvcut", ecutvcut)
       call iotk_write_dat(iunpun, "exx_fraction", exx_fraction)
       call iotk_write_dat(iunpun, "screening_parameter", screening_parameter)
+      call iotk_write_dat(iunpun, "exx_is_active", exx_is_active)
       CALL iotk_write_end(iunpun, "EXACT_EXCHANGE" )
     END SUBROUTINE write_exx
 #endif

PW/pw_restart.f90

@@ -112,7 +112,7 @@ MODULE pw_restart
                                        nproc_image, &
                                        root_pool, intra_pool_comm, inter_pool_comm, intra_image_comm 
 #ifdef EXX
-      USE funct,                ONLY : get_exx_fraction, get_screening_parameter
+      USE funct,                ONLY : get_exx_fraction, get_screening_parameter, exx_is_active
       USE exx,                  ONLY : x_gamma_extrapolation, nq1, nq2, nq3, &
                                        exxdiv_treatment, yukawa, ecutvcut
 #endif
@@ -393,7 +393,7 @@ MODULE pw_restart
          CALL write_exx( x_gamma_extrapolation, nq1, nq2, nq3, &
                          exxdiv_treatment, yukawa, ecutvcut, &
                          get_exx_fraction(), &
-                         get_screening_parameter() )
+                         get_screening_parameter(), exx_is_active() )
 #endif
          !
 !-------------------------------------------------------------------------------
@@ -3215,7 +3215,7 @@ MODULE pw_restart
       ! ... read EXX variables
       !
       USE funct,                ONLY : set_exx_fraction, set_screening_parameter, &
-                                       enforce_input_dft
+                                       enforce_input_dft, start_exx
       USE exx,                  ONLY : x_gamma_extrapolation, nq1, nq2, nq3, &
                                        exxdiv_treatment, yukawa, ecutvcut
       IMPLICIT NONE
@@ -3224,6 +3224,7 @@ MODULE pw_restart
       INTEGER,          INTENT(OUT) :: ierr
       CHARACTER(LEN=80) :: dft_name
       REAL(DP) :: exx_fraction, screening_parameter
+      LOGICAL :: exx_is_active
       !
       IF ( ionode ) THEN
          CALL iotk_open_read( iunpun, FILE = TRIM( dirname ) // '/' // &
@@ -3245,6 +3246,7 @@ MODULE pw_restart
          call iotk_scan_dat(iunpun, "ecutvcut", ecutvcut)
          call iotk_scan_dat(iunpun, "exx_fraction", exx_fraction)
          call iotk_scan_dat(iunpun, "screening_parameter", screening_parameter)
+         call iotk_scan_dat(iunpun, "exx_is_active", exx_is_active)
          CALL iotk_scan_end( iunpun, "EXACT_EXCHANGE" )
          CALL iotk_close_read( iunpun )
       END IF
@@ -3258,9 +3260,11 @@ MODULE pw_restart
       CALL mp_bcast( ecutvcut, ionode_id, intra_image_comm )
       CALL mp_bcast( exx_fraction, ionode_id, intra_image_comm )
       CALL mp_bcast( screening_parameter, ionode_id, intra_image_comm )
+      CALL mp_bcast( exx_is_active, ionode_id, intra_image_comm )
       call enforce_input_dft(dft_name)
       call set_exx_fraction(exx_fraction)
       call set_screening_parameter(screening_parameter)
+      if (exx_is_active) call start_exx
       RETURN
       !
     END SUBROUTINE read_exx

PW/read_file.f90

@@ -250,14 +250,15 @@ SUBROUTINE read_file()
      rho%of_g(:,is) = psic(nl(:))
      !
   END DO
+
+#ifdef EXX
+  call pw_readfile('exx', ierr)
+#endif
   !
   ! ... recalculate the potential
   !
   CALL v_of_rho( rho, rho_core, rhog_core, &
                  ehart, etxc, vtxc, eth, etotefield, charge, v )
-#ifdef EXX
-  call pw_readfile('exx', ierr)
-#endif
   !
   ! ... reads the wavefunctions and writes them in 'distributed' form 
   ! ... to unit iunwfc (for compatibility)