# Let's implement a partially observable world (AIMA ch. 4).

• Jan 28, 2013 · 8:00 PM

We're going to break up 4.11 into several subproblems; the first of which is to implement a partially observable world containing disjoint, convex polygons and which has the following properties:

• The percept will be a list of the positions, relative to the agent, of the visible vertices.
• The percept does not include the position of the robot! The robot must learn its own position from the map; for now, you can assume that each location has a different 'view."
• Each action will be a vector describing a straight-fine path to follow. If the path is unobstructed, the action succeeds; otherwise, the robot stops at the point where its path first intersects an obstacle. If the agent returns a zero motion vector and is at the goal (which is fixed and known), then the environment teleports the agent to a random location (not inside an obstacle).
• The performance measure charges the agent l point for each unit of distance traversed and awards 1000 points each time the goal is reached.

• ##### Glenn B.

I just learned about the CCW (counter-clockwise) test for line segments intersecting. Very nice. http://compgeom.cs.uiuc.edu/~jeffe/teaching/373/notes/x06-sweepline.pdf

January 30, 2013

• ##### Peter D.

That's pretty cool; did you handle the degenerate cases? Also, I think I have PTSD with respect to the word "sweepline" from trying to implement Fortune's algorithm for Voronois.

January 31, 2013

• ##### Glenn B.

Great conversation clarified the problem, and has led to some cool code.

January 30, 2013

• ##### Peter D.

Great; we made some great progress planning out the partially observable world. Prasan had a pretty good proof-of-concept, too.

January 29, 2013

• ##### Nesim S.

can't make it there physically

January 28, 2013

• ##### Peter D.

Sorry, Nesim; we'll set one up next week!

January 28, 2013

• ##### Glenn B.

Be there in fifteen.

January 28, 2013

• ##### Prasan S.

On my way

January 28, 2013

• ##### Prasan S.

On my way

January 28, 2013

• ##### Patrick N

Crud. Had to cancel because I'm behind on a project. By the way, does everyone in the group have their own copy of the Russell/Norvig book?

January 28, 2013

• ##### Peter D.

Some of us do; but most of us just use the PDF. Should I send it to you?

January 28, 2013

• ##### Prasan S.

In

January 26, 2013

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