!
! Copyright (C) 2001-2009 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 .
!
!-----------------------------------------------------------------------
subroutine gwq_recover
!-----------------------------------------------------------------------
!
! This subroutine tests if a xml restart file exists with the
! information of where the code stopped and, if appropriate the
! partial dynamical matrix and the partial effective charges.
! if (rec_code>2) done_irr, comp_irr
! info on calculated irreps - overrides initialization in gwq_setup.
! The xml file is in the
! directory _gwprefix.gwsave. The xml file contains
! where_rec a string with information of the point where the calculation
! stopped
! rec_code_read where_rec status description
!
! -1000 Nothing has been read. There is no recover file.
! -40 gwq_setup Only the displacements u have been read from file
! -30 gwq_init u and dyn(0) read from file
! -25 not active yet. Restart in solve_e_fpol
! -20 solve_e all previous. Stopped within solve_e. There
! should be a recover file.
! -10 solve_e2 epsilon and zstareu are available if requested.
! Stopped within solve_e2. There should be a
! recover file.
! 2 gwescf all previous, raman tenson and elop tensor are
! available if required.
! 10 solve_linter all previous. Stopped within solve linter.
! There should be a recover file.
! 20 gwqscf all previous dyn_rec(irr) and zstarue0(irr) are
! available.
! 30 dynmatrix all previous, dyn and zstarue are available.
!
! The logic of the phonon code recover is the following:
! The recover variable is read from input and never changed. If it is
! false it disables completely the recover.
! The control of the code is given by the arrays:
! comp_iq, done_iq : for each q point if it has to be calculated or
! if it is already available. These are calculated
! only once by check_initial_status or read from file
! by the same routine.
! comp_irr, done_irr : for each irreducible representation if it has
! to be calculated or if it is already calculated.
! The latter variables are valid only for the current
! q and are calculated in gwq_setup and modified here
! if something is on the file.
! epsil, done_epsil, zeu, done_zeu, zue, done_zue, lraman, done_lraman,
! elop, done_elop ... control the electric field calculations. These are
! set by prepare_q, or read from file by gwq_setup.
!
! The position where the code stopped is in the variable rec_code_read
! defined above. This variable allows to exit from a routine if the quantity
! calculated by this routine is already saved on file.
! It is the responsibility of the routine (not of the calling code)
! to known if it has to make the calculation or just exit because the
! value of rec_code_read is too high.
!
! if rec_code_read = (-25), -20, -10, 10
! It is expected that an unformatted recover file exists.
! The following data are in the
! unformatted file and are read by
! routines solve_e (-20), solve_e2 (-10), solve_linter (10):
! iter, dr2, convt
! info on status of linear-response calculation for a given irrep.
! dvscfin
! self-consistent potential for current iteration and irrep
! if (okpaw) dbecsum
! the change of the D coefficients calculated so far.
! if (okvan) int1, int2, int3
! arrays used with US potentials : int1 and int2 calculated in dvanqq,
! int3 calculatec in newdq (depends upon self-consistency)
!
! rec_code_read is valid only for the first q. For the following q
! it is reset to -1000 in clean_pw_gw. So the recover file allows to
! restart only the current q. However information on other q could
! be available in the directory gwsave, so this routine reads the
! appropriate files and reset comp_irr and done_irr if appropriate.
!
! NB: The restart of the electron-phonon part is not available yet.
!
USE kinds, ONLY : DP
USE io_global, ONLY : stdout
USE gw_restart, ONLY : gw_readfile
USE control_gw, ONLY : epsil, rec_code_read, all_done, where_rec,&
zeu, done_epsil, done_zeu, ext_recover, recover
USE partial, ONLY : comp_irr, done_irr
USE modes, ONLY : nirr
!
implicit none
!
integer :: irr, ierr
! counter on representations
! error code
logical :: exst
character(len=256) :: filename
ierr=0
IF (recover) THEN
CALL gw_readfile('data',ierr)
IF (rec_code_read==-40) THEN
WRITE( stdout, '(/,4x," Modes are read from file ")')
ELSEIF (rec_code_read==-20) THEN
WRITE( stdout, '(/,4x," Restart in Electric Field calculation")')
ELSEIF (rec_code_read==-10) then
WRITE( stdout, '(/,4x," Restart in Raman calculation")')
ELSEIF (rec_code_read==2) THEN
WRITE( stdout, '(/,4x," Restart after Electric Field calculation")')
ELSEIF (rec_code_read==10.OR.rec_code_read==20) then
WRITE( stdout, '(/,4x," Restart in Phonon calculation")')
ELSEIF (rec_code_read==30) then
WRITE( stdout, '(/,4x," Restart after Phonon calculation")')
ELSE
call errore ('gwq_recover', 'wrong restart data file', -1)
ierr=1
ENDIF
ENDIF
!
ext_recover = ext_recover .AND. ierr==0
!
! The case in which everything has been already calculated and we just
! recollect all the results must be treated in a special way (it does
! not require any initialization).
! We check here if everything has been done
!
RETURN
END SUBROUTINE gwq_recover