vacuum-world environment along the following lines:
(defstructure (nxm-vacuum-world (:include vacuum-world ;; your code goes here )) "An mxn grid with dirty rooms.")
Then implement an agent with internal state that sucks up all of the
dirt, returns to its home position, and shuts off. You will need to
decide what state information the agent needs to maintain. You can
define your agent by specializing the existing general agent
agent. The general structure of the code should look like the
following:
(defstructure (state-vacuum-agent ; name of this agent
(:include agent ; specializes the AGENT class
(program
(let ((location '(1 1)) ; state variables with their initial values
(heading 'east))
#'(lambda (percept)
;; use percept to update state
;; choose action
;; use chosen action to update the state
;; return chosen action
))))))
In this code, the let special form is used to define two
state variables location and heading. You
may decide to use different state variables or to include additional
state variables. The lambda expression defines a
function that is closed over these state variables. This makes
these state variables act like static variables in C or
C++. Any expression in the body of this lambda
expression can access the location and
heading variables. The agent's program
entry must be a function of one argument (the percept), and
it must return the chosen action.
In the vacuum-world
environment, the percept is a list of three elements: (bump dirt
home). Each of these elements is a boolean indicating whether
the bump sensor, dirt sensor, and home sensor are returning true.
Please note that it is possible to have more than one "unit" of dirt
within a cell. Hence, after doing a "suck" action, there may still be
dirt in the cell.
While debugging your agent, I suggest that you constrain the world to be fairly small (e.g., 4 by 4, which means 6 by 6 when you count the walls). To test your agent, use
(run-environment (make-nxm-vacuum-world :max-steps 100))
This will run the default agent for up to 100 steps on the
nxm-vacuum-world.
When you have your agent debugged, you should compare its performance
to the agent called reactive-vacuum-agent that is
provided by Russell and Norvig. You do this using the following:
(agent-trials 'make-nxm-vacuum-world
'(state-vacuum-agent reactive-vacuum-agent)
:n 10)
where the 10 specifies that each agent will be run on 10 random
nxm-vacuum-world's and the results averaged and
reported.
agent-trials run. Your code should clearly explain what
it is doing. In particular, please explain the meaning of each of
your state variables. You should try to get a good score on the
performance criterion (which gives 100 points for each dirt object you
vacuum up, -1 point for each action, and -1000 points if the agent is
not in its home location when it shuts off. Please email your
solution to the TA {wangha@cs.orst.edu) and also turn in a hardcopy at the
start of class.