In tutorial batch processing, when I set the motion planner as student, there are many exception occurred in run_parallel_processing(). Why would this happened 
Hi a11,
If astar works still properly, I would recommand you to carefully check your implementation.
Best,
Mingxuan
thanks a lot, I have figued out what is the problem, there are something wrong with my code. I changed these codes. But there is a new problem , when I try to run run_parallel_processing(), many Time out showed. I try to fix it by reducing the number of factors in heuristic function, like cutting orientation difference out, however it not works. Have I missed out something 
Hi a11,
Good to know that you have solved your problem.
Since I should not give explicit hint on what kind of implementation is good or bad, I might can only give you one suggestion: The code from student_example planner serves just as an example of how you can implement a new heuristic, but this example is not necessarily good. You might refer to what we provide in tutorials and come up with a heuristic by yourself.
Hope this can help you. Your further questions are always welcomed.
Best,
Mingxuan