! -----------------------------------------------------------------------------
! BSD 3-Clause License
!
! Copyright (c) 2019, Science and Technology Facilities Council.
! All rights reserved.
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! * Redistributions of source code must retain the above copyright notice, this
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! * Redistributions in binary form must reproduce the above copyright notice,
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!   this software without specific prior written permission.
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! THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
! AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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! FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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! OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
! -----------------------------------------------------------------------------
! Author: A. R. Porter, STFC Daresbury Lab.
! Modified: S. Siso, STFC Daresbury Laboratory

module kern_use_var_mod
  use argument_mod
  use kernel_mod
  use kind_params_mod
  use grid_mod
  implicit none

  type, extends(kernel_type) :: kern_use_var
     type(go_arg), dimension(1) :: meta_args =              &
          (/ go_arg(GO_READWRITE, GO_CT, GO_POINTWISE) /)
     !> This kernel writes only to internal points of the
     !! simulation domain.
     integer :: ITERATES_OVER = GO_INTERNAL_PTS

     integer :: index_offset = GO_OFFSET_SW

  contains
    procedure, nopass :: code => kern_use_var_code
  end type kern_use_var

contains

  subroutine kern_use_var_code(i, j, fld)
    use data_mod, only: gravity
    integer, intent(in) :: i, j
    real(go_wp), dimension(:,:), intent(inout) :: fld

    fld(i,j) = gravity * fld(i,j)

  end subroutine kern_use_var_code
  
end module kern_use_var_mod
