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 Robotics / 6817
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Subject: 
Re: New Lego challenge !
Newsgroups: 
lugnet.robotics
Date: 
Mon, 13 Sep 1999 10:56:08 GMT
Viewed: 
471 times
  
In lugnet.robotics, Laurentino Martins writes:
At 03:35 13-09-1999 Monday , Mike Poindexter wrote:
Got it figured out.  Using the principles of right handed recursion, you can
have the robot follow the right wall and it will eventually get to the light
and also get out of the maze again.

Incidentally, right handed recursion will get you out of any labyrinth
provided that you are not starting inside it already.  If you are already in
it, it will likely work there as well.  This would then allow the robot to
work in almost any maze you create.

Yes, unfortunately the current firmware implementation from LEGO doesn't have
a call stack, so you can not build recursive routines. :-(

Actually you don't need a recursive algorithm to apply the right hand rule.
Simply follow either the right (or left) wall and you'll arrive at the exit.
For a maze with no exit but a "special point" to reach inside (like Philippe's
one), the rule works if the point is not surrounded by a circular path. As you
can easily see, the right (or left) hand rule works perfectly with Philippe's
labyrinth.

On the other hand I can imagine labyrinths where that bot would never be able
to do anything out of them.

The simplest way to make one of these is to violate the previous constraint
and surround the point to reach with a circular path.

Mario

http://www.geocities.com/~marioferrari



Message has 1 Reply:
  Re: New Lego challenge !
 
(...) To be more specific, the "right hand rule" is not a recursive algorithm at all in the classic sense. We like to think of it that way because the "traveler" will traverse parts of the maze repeatedly, in the worst case the whole maze. However, (...) (25 years ago, 13-Sep-99, to lugnet.robotics)

Message is in Reply To:
  Re: New Lego challenge !
 
(...) Yes, unfortunately the current firmware implementation from LEGO doesn't have a call stack, so you can not build recursive routines. :-( On the other hand I can imagine labyrinths where that bot would never be able to do anything out of them. (...) (25 years ago, 13-Sep-99, to lugnet.robotics)

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