subroutine get_stream_tn_parallel
    use omp_lib
    
    implicit none
    integer :: i, thread_id,partial_Sum,total_Sum

    t1_vertex(0)%value = t0_vertex(0)%value - dt * (t0_vertex(0)%value - t0_vertex(nx)%value)/dx
    !$OMP PARALLEL PRIVATE(partial_Sum) SHARED(total_Sum)
    
    !$OMP DO
    do i = 1,nx + nghost
        t1_vertex(i)%value = t0_vertex(i)%value - dt * (t0_vertex(i)%value - t0_vertex(i-1)%value)/dx
        !thread_id = OMP_GET_THREAD_NUM()
        !print *, "Upwind process: ", thread_id
    enddo
    !$OMP end DO
    
    !$OMP DO
    do i = 1 - nghost, nx + nghost
        t0_vertex(i)%value = t1_vertex(i)%value
    enddo
    !$OMP end DO 
    !$OMP END PARALLEL
end subroutine get_stream_tn_parallel