SUBROUTINE cft3sig( f, n1, n2, n3, nx1, nx2, nx3, sign )

  USE fft_base,     ONLY : dffts
  USE kinds,        ONLY : DP
  USE fft_parallel, ONLY : tg_cft3s

IMPLICIT NONE

INTEGER,     INTENT(IN)    :: n1, n2, n3, nx1, nx2, nx3, sign
COMPLEX(DP), INTENT(INOUT) :: f(nx1*nx2*nx3)

CALL start_clock('cft3sig')

  IF (sign == 1) THEN
     !
     CALL cfft3dsig(f, n1, n2, n3, nx1, nx2, nx3,1)
     !
  ELSE IF (sign == -1) 
     !
     CALL cfft3dsig(f, n1, n2, n3, nx1, nx2, nx3,-1)
     !
  ELSE 
     !
     CALL errore( 'cft3sig', 'invalid number for fft?', 1 )
     !
  ENDIF

CALL stop_clock('cft3sig')

END cft3sig