CalculateSolutionGradient_DGModel1D_t Subroutine

  subroutine CalculateSolutionGradient_DGModel1D_t(this)
    implicit none
    class(DGModel1D_t),intent(inout) :: this

    call this%solution%AverageSides()

    this%solution%boundarynormal(1,:,:) = -this%solution%avgBoundary(1,:,:) ! Account for left facing normal
    this%solution%boundarynormal(2,:,:) = this%solution%avgBoundary(2,:,:) ! Account for right facing normal

    call this%solution%MappedDGDerivative(this%solutionGradient%interior)

    ! interpolate the solutiongradient to the element boundaries
    call this%solutionGradient%BoundaryInterp()

    ! perform the side exchange to populate the
    ! solutionGradient % extBoundary attribute
    call this%solutionGradient%SideExchange(this%mesh)

  endsubroutine CalculateSolutionGradient_DGModel1D_t