UpdateGRK4_DGModel3D_t Subroutine

  subroutine UpdateGRK4_DGModel3D_t(this,m)
    implicit none
    class(DGModel3D_t),intent(inout) :: this
    integer,intent(in) :: m
    ! Local
    integer :: i,j,k,iVar,iEl

    do concurrent(i=1:this%solution%N+1,j=1:this%solution%N+1, &
                  k=1:this%solution%N+1,iel=1:this%mesh%nElem,ivar=1:this%solution%nVar)

      this%workSol%interior(i,j,k,iEl,iVar) = rk4_a(m)* &
                                              this%workSol%interior(i,j,k,iEl,iVar)+ &
                                              this%dSdt%interior(i,j,k,iEl,iVar)

      this%solution%interior(i,j,k,iEl,iVar) = &
        this%solution%interior(i,j,k,iEl,iVar)+ &
        rk4_g(m)*this%dt*this%workSol%interior(i,j,k,iEl,iVar)

    enddo

  endsubroutine UpdateGRK4_DGModel3D_t