Chimie Théorique » Opt'n Path

subroutine egrad_vasp(e,geomcart,gradcart)

  ! This routines calculates the energy and the gradient of 

  ! a molecule, using VASP

!----------------------------------------------------------------------

!  Copyright 2003-2014 Ecole Normale Supérieure de Lyon, 

!  Centre National de la Recherche Scientifique,

!  Université Claude Bernard Lyon 1. All rights reserved.

!

!  This work is registered with the Agency for the Protection of Programs 

!  as IDDN.FR.001.100009.000.S.P.2014.000.30625

!

!  Authors: P. Fleurat-Lessard, P. Dayal

!  Contact: optnpath@gmail.com

!

! This file is part of "Opt'n Path".

!

!  "Opt'n Path" is free software: you can redistribute it and/or modify

!  it under the terms of the GNU Affero General Public License as

!  published by the Free Software Foundation, either version 3 of the License,

!  or (at your option) any later version.

!

!  "Opt'n Path" is distributed in the hope that it will be useful,

!  but WITHOUT ANY WARRANTY; without even the implied warranty of

!

!  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

!  GNU Affero General Public License for more details.

!

!  You should have received a copy of the GNU Affero General Public License

!  along with "Opt'n Path". If not, see <http://www.gnu.org/licenses/>.

!

! Contact The Office of Technology Licensing, valorisation@ens-lyon.fr,

! for commercial licensing opportunities.

!----------------------------------------------------------------------

  use Path_module, only : Nat, renum,Order,OrderInv, Coord, &

       ProgExe,Latr,FrozAtoms

  use Io_module

  !

  IMPLICIT NONE

  ! Energy (calculated if F300K=.F., else estimated)

  REAL(KREAL), INTENT (OUT) :: e

  ! Nb degree of freedom

  REAL(KREAL), INTENT (IN) :: geomcart(Nat,3)

  ! Gradient calculated at Geom geometry

  REAL(KREAL), INTENT (OUT) :: gradcart(3*NAt)

  ! ======================================================================

  character(LCHARS) :: LINE

  REAL(KREAL) :: Pi

  INTEGER(KINT) :: iat, i, n3at

  REAL(KREAL) :: RTmp1, RTmp2, RTmp3

  !

  CHARACTER(132), PARAMETER :: FileIn='POSCAR', FileOut='OUTCAR'

  CHARACTER(VLCHARS), SAVE :: RunCommand

!  REAL(KREAL), ALLOCATABLE :: GeomTmpC(:), GeomTmp(:)

  LOGICAL :: Debug

  INTERFACE

     function valid(string) result (isValid)

       CHARACTER(*), intent(in) :: string

       logical                  :: isValid

     END function VALID

  END INTERFACE

  Pi=dacos(-1.0d0)

  debug=valid('EGRAD')

  if (debug) Call header('Entering Egrad_VASP')

  n3at=3*nat

!  ALLOCATE(GeomTmpC(n3at))

  gradcart=0.

  E=0.

  RunCommand=Trim(ProgExe) 

  IF (DEBUG) WRITE(*,*)'RunCommand:',TRIM(RunCommand)

  ! we create the input file

!   write(*,*) "Coucou 2"

  OPEN(IOTMP,File=FileIn)

  ! we convert the coordinates into Cartesian coordinates

!     GeomTmpC=Reshape(GeomCart,SHAPE=(/3*Nat/))

   Call PrintGeomVasp(Vasp_Title,geomcart,Latr,FrozAtoms,IoTmp)

  CLOSE(IOTMP)

  IF (debug) THEN

     WRITE(*,*) 'DBG EGRAD ' //  Trim(FileIn),' COORD=',TRIM(COORD)

     call system('cat ' // Trim(FileIn))

  END IF

  call system(RunCommand)

  if (debug) WRITE(*,*) 'DBG EGRAD_VASP, back from calculation'

!  if (debug) WRITE(*,*) "DBG EGRAD_VASP Order(I)",Order(1:Nat)

  ! Whatever the coordinate system, we read the cartesian gradient

  ! and we convert it to Zmat or other if needed

  OPEN(IOTMP,FILE=FileOut, STATUS='old')

  ! We first search for the forces

  READ(IOTMP,'(A)',END=999,ERR=999) LINE

! We search for the  last part of the OUTCAR file, after wavefunction is converged

  DO WHILE (INDEX(LINE,'EDIFF is reached')==0)

     READ(IOTMP,'(A)',END=999,ERR=999) LINE

  END DO

  READ(IOTMP,'(A)',END=999,ERR=999) LINE

  DO WHILE (INDEX(LINE,'TOTEN')==0)

     READ(IOTMP,'(A)',END=999,ERR=999) LINE

  END DO

  Line=Line(26:)

  READ(LINE,*) E

  if (debug) WRITE(*,'(1X,A,F20.6)') "DBG Egrad_VASP E=",E

! We search for the forces

  DO WHILE (INDEX(LINE,'TOTAL-FORCE')==0)

     READ(IOTMP,'(A)',END=999,ERR=999) LINE

  END DO

  READ(IOTMP,'(A)',END=999,ERR=999) LINE

  DO I=1,Nat

     Iat=I

     IF (renum) Iat=Order(I)

     READ(IOTMP,*,END=999,ERR=999)  Rtmp1,RTmp2,RTmp3,GradCart(3*Iat-2:3*Iat)

  END DO

  if (debug) THEN

     WRITE(*,*) "DBG EGRAD_VASP - GradCart=FORCES - original order"

     DO I=1,Nat

        Iat=Order(I)

        WRITE(*,'(1X,I5,3(1X,F20.6))') I,GradCart(3*Iat-2:3*Iat)

     END DO

     WRITE(*,*) "DBG EGRAD_VASP - GradCart=FORCES - internal order"

     DO I=1,Nat

        Iat=Order(I)

        WRITE(*,'(3(1X,I5),3(1X,F20.6))') I,Iat,OrderInv(I),GradCart(3*I-2:3*I)

     END DO

  END IF

  ! VASP gives the Forces in eV/Angstrom, so we convert it into the 

  ! gradient in ua/Angstrom 

    gradCart=-1.0d0*ev2Au*gradCart

  !  if (debug.AND.(COORD.EQ.'ZMAT')) THEN

  !     DO WHILE (INDEX(LINE,'Internal Coordinate Forces')==0)

  !        READ(IOTMP,'(A)') LINE

  !!        WRITE(*,*) 'Pas bon:' // TRIM(LINE)

  !     END DO

  !     WRITE(*,*) TRIM(LINE)

  !     DO I=1,Nat+2

  !        READ(IOTMP,'(A)') LINE

  !        WRITE(*,*) TRIM(LINE)

  !     END DO

  !  END IF

  CLOSE(IOTMP)

!  DeALLOCATE(GeomTmpC)

  if (debug) Call header('Egrad_VASP Over')

  RETURN

999 CONTINUE

  WRITE(*,*) 'We should not be here !!!!'

  STOP

  ! ======================================================================

end subroutine egrad_vasp