From 27b4f5e4954f25ad4cf9bc4b402f65ac88c1cd09 Mon Sep 17 00:00:00 2001
From: giannozz <p.giannozzi@gmail.com>
Date: Fri, 2 Oct 2020 08:47:51 +0200
Subject: [PATCH] Direct call to fft_parallel replaced by call to interface
 routine. This removes the only instance of USE fft_parallel in QE BEWARE: not
 guaranteed to work

---
 GWW/pw4gww/fft_custom.f90 | 70 +++++++++------------------------------
 GWW/pw4gww/make.depend    |  3 +-
 2 files changed, 17 insertions(+), 56 deletions(-)

diff --git a/GWW/pw4gww/fft_custom.f90 b/GWW/pw4gww/fft_custom.f90
index aa817ec28..b8e2c8456 100644
--- a/GWW/pw4gww/fft_custom.f90
+++ b/GWW/pw4gww/fft_custom.f90
@@ -664,68 +664,30 @@ SUBROUTINE cft3t( fc, f, n1, n2, n3, nx1, nx2, nx3, sign )
   ! ...  and all planes(i) are set to 1
   !
 
-  USE kinds,        ONLY : DP
-  USE fft_parallel, ONLY : tg_cft3s
-  USE fft_scalar,   ONLY : cfft3ds, cfft3d  !  common scalar fft driver
-  USE io_global, ONLY : stdout
+  USE kinds,         ONLY : DP
+  USE fft_interfaces,ONLY : fwfft, invfft
   !
   IMPLICIT NONE
   !
   TYPE(fft_cus) :: fc
   INTEGER,     INTENT(IN)    :: n1, n2, n3, nx1, nx2, nx3, sign
-
-#if defined (__MPI) && !defined(__USE_3D_FFT)
-!
-  COMPLEX(DP), INTENT(INOUT) :: f( fc%dfftt%nnr )
+  COMPLEX(DP), INTENT(INOUT) :: f(:)
+  CHARACTER(LEN=4) :: fft_kind
   !
-  ! ... call the general purpose parallel driver
-  !
-
-  call start_clock('cft3t')
-  CALL tg_cft3s( f, fc%dfftt, sign )
-  call stop_clock('cft3t')
-  !
-#else
-
-  !
-  ! ... serial case
-  !
-  COMPLEX(DP), INTENT(INOUT) :: f(nx1*nx2*nx3)
-  !
-  !
-
-  !
-  ! ... sign = +-1 : complete 3d fft (for rho and for the potential)
-  !
-  IF ( sign == 1 ) THEN
-     !
-     CALL cfft3d( f, n1, n2, n3, nx1, nx2, nx3, 1, 1 )
-     !
-  ELSE IF ( sign == -1 ) THEN
-     !
-     CALL cfft3d( f, n1, n2, n3, nx1, nx2, nx3, 1, -1 )
-     !
-     ! ... sign = +-2 : if available, call the "short" fft (for psi's)
-     !
-  ELSE IF ( sign == 2 ) THEN
-     !
-     CALL cfft3ds( f, n1, n2, n3, nx1, nx2, nx3, 1, 1, fc%dfftt%isind, fc%dfftt%iplw )
-     !
-  ELSE IF ( sign == -2 ) THEN
-     !
-     CALL cfft3ds( f, n1, n2, n3, nx1, nx2, nx3, 1, -1, fc%dfftt%isind, fc%dfftt%iplw )
-     !
+  IF ( ABS(sign) == 1 ) THEN
+     fft_kind = 'Rho'
+  ELSE IF ( ABS(sign) == 2 ) THEN
+     fft_kind = 'Wave'
   ELSE
-     !
-     CALL errore( 'cft3t', 'what should i do?', 1 )
-     !
+     CALL errore('cft3t','wrong argument "sign"?',1)
   END IF
-  !
-
-  !
-#endif
-  !
-
+  CALL start_clock('cft3t')
+  IF ( sign < 0 ) THEN
+     CALL fwfft ( fft_kind, f, fc%dfftt )
+  ELSE
+     CALL invfft( fft_kind, f, fc%dfftt )
+  END IF
+  CALL  stop_clock('cft3t')
   RETURN
   !
 END SUBROUTINE cft3t
diff --git a/GWW/pw4gww/make.depend b/GWW/pw4gww/make.depend
index daee1619a..d40dc530a 100644
--- a/GWW/pw4gww/make.depend
+++ b/GWW/pw4gww/make.depend
@@ -117,8 +117,7 @@ fake_conduction.o : ../../UtilXlib/mp.o
 fake_conduction.o : ../../upflib/uspp.o
 fake_conduction.o : fft_custom.o
 fake_conduction.o : mp_wave_parallel.o
-fft_custom.o : ../../FFTXlib/fft_parallel.o
-fft_custom.o : ../../FFTXlib/fft_scalar.o
+fft_custom.o : ../../FFTXlib/fft_interfaces.o
 fft_custom.o : ../../FFTXlib/fft_support.o
 fft_custom.o : ../../FFTXlib/fft_types.o
 fft_custom.o : ../../FFTXlib/stick_base.o