!
  !--------------------------------------------------------
  subroutine readdvscf ( dvscf, recn, iq, nqc )
  !--------------------------------------------------------
  !
  !  open dvscf files as direct access, read, ad close again
  !
  !  Feliciano Giustino, UC Berkeley
  !
  !-------------------------------------------------------------
  !
#include "f_defs.h"
  use io_files, only : prefix, tmp_dir, dvscf_dir
  use units_ph, only : lrdrho
  use kinds,    only : DP
  USE lsda_mod, ONLY : nspin
  USE gvect,    ONLY : nrxx
  use pwcom
#ifdef __PARA
  use mp_global,only : nproc, nproc_pool, me_pool, mpime
  use para,     only : nprocp, mypool
  use mp_global,only : npool
#endif
  !
  implicit none
  integer :: recn, iq, nqc, iudvscf
  !  perturbation number
  !  the current q point
  !  the total number of qpoints in the list
  !  the temporary unit number
  complex(kind=DP) :: dvscf ( nrxx , nspin) 
  !
  integer :: unf_recl
  character (len=256) :: tempfile
  character (len=3) :: filelab
  ! file label 

  iudvscf = 80
  !
  !  the call to set_ndnmbr is just a trick to get quickly
  !  a file label by exploiting an existing subroutine
  !  (if you look at the sub you will find that the original 
  !  purpose was for pools and nodes)
  !
  call set_ndnmbr ( 0, iq, 1, nqc, filelab)
  tempfile = trim(dvscf_dir) // trim(prefix) // '.dvscf_q' // filelab
  !
  unf_recl = DIRECT_IO_FACTOR * lrdrho
  !
  !  open the dvscf file, read and close
  !
  open  (iudvscf, file = tempfile, form = 'unformatted', &
          access = 'direct', recl = unf_recl)
  read  (iudvscf, rec = recn) dvscf
  close (iudvscf, status = 'keep')
  !
  !
  return
  end subroutine readdvscf
  !--------------------------------------------------------
  !