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

!                      Code_Saturne version 4.2.0
!                      --------------------------
! This file is part of Code_Saturne, a general-purpose CFD tool.
!
! Copyright (C) 1998-2015 EDF S.A.
!
! This program is free software; you can redistribute it and/or modify it under
! the terms of the GNU General Public License as published by the Free Software
! Foundation; either version 2 of the License, or (at your option) any later
! version.
!
! This program 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 General Public License for more
! details.
!
! You should have received a copy of the GNU General Public License along with
! this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
! Street, Fifth Floor, Boston, MA 02110-1301, USA.

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

!===============================================================================
! Purpose:
! -------

! \file cs_user_extra_operations-global_efforts.f90
! This is an example of cs_user_extra_operations.f90 which
! performs global efforts

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

!-------------------------------------------------------------------------------
! Arguments
!______________________________________________________________________________.
!  mode           name          role                                           !
!______________________________________________________________________________!
!> \param[in]     nvar          total number of variables
!> \param[in]     nscal         total number of scalars
!> \param[in]     dt            time step (per cell)
!_______________________________________________________________________________

subroutine cs_f_user_extra_operations &
 ( nvar   , nscal  ,                                              &
   dt     )

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

!===============================================================================
! Module files
!===============================================================================

use paramx
use dimens, only: ndimfb
use pointe
use numvar
use optcal
use cstphy
use cstnum
use entsor
use lagpar
use lagran
use lagdim
use parall
use period
use ppppar
use ppthch
use ppincl
use mesh
use field
use field_operator
use turbomachinery

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

implicit none

! Arguments

integer          nvar   , nscal

double precision dt(ncelet)

! Local variables

!< [loc_var_dec]
integer          ifac
integer          ii
integer          ilelt  , nlelt

double precision xfor(3)
double precision, dimension(:,:), pointer :: bfprp_for

integer, allocatable, dimension(:) :: lstelt
!< [loc_var_dec]

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

!===============================================================================
! Initialization
!===============================================================================

    if (ntcabs.eq.1) then
      open(file='drag_lift.dat',unit=impusr(1))
      write(impusr(1),'(4(A,1X))') ' time ', ' Drag ', ' Lift ',' Lift2 '
      close(unit=impusr(1))
    endif

if (iforbr.ge.0) call field_get_val_v(iforbr, bfprp_for)

! Allocate a temporary array for cells or interior/boundary faces selection
allocate(lstelt(max(ncel,nfac,nfabor)))

!===============================================================================
! Example: compute global efforts on a subset of faces
!===============================================================================

! If efforts have been calculated correctly:

!< [example_1]
if (iforbr.ge.0) then

  do ii = 1, ndim
    xfor(ii) = 0.d0
  enddo

  call getfbr('wall', nlelt, lstelt)
  !==========

  do ilelt = 1, nlelt

    ifac = lstelt(ilelt)

    do ii = 1, ndim
      xfor(ii) = xfor(ii) + bfprp_for(ii, ifac)
    enddo

  enddo

  if (irangp.ge.0) then
    call parrsm(ndim,xfor)
  endif

    do ii = 1, ndim
      xfor(ii) = 2.0*xfor(ii)
    enddo

    open(file='drag_lift.dat',unit=impusr(1),position='append')
    write(impusr(1),'(4(E12.5,1X))') ttcabs,xfor(1),xfor(2),xfor(3)
    write(nfecra,'(4(E12.5,1X))') ttcabs,xfor(1),xfor(2),xfor(3)
    close (unit=impusr(1))

endif
!< [example_1]

! Deallocate the temporary array
deallocate(lstelt)


return
end subroutine cs_f_user_extra_operations