aimacode · norvig · Aug 2, 2018 · Jul 18, 2018 · Jul 18, 2018 · Jul 18, 2018
diff --git a/README.md b/README.md
@@ -88,7 +88,7 @@ Here is a table of algorithms, the figure, name of the algorithm in the book and
 | 5.3    | Minimax-Decision                  | `minimax_decision`            | [`games.py`][games]             | Done | Included |
 | 5.7    | Alpha-Beta-Search                 | `alphabeta_search`            | [`games.py`][games]             | Done | Included |
 | 6      | CSP                               | `CSP`                         | [`csp.py`][csp]                 | Done | Included |
-| 6.3    | AC-3                              | `AC3`                         | [`csp.py`][csp]                 | Done |          |
+| 6.3    | AC-3                              | `AC3`                         | [`csp.py`][csp]                 | Done | Included |
 | 6.5    | Backtracking-Search               | `backtracking_search`         | [`csp.py`][csp]                 | Done | Included |
 | 6.8    | Min-Conflicts                     | `min_conflicts`               | [`csp.py`][csp]                 | Done | Included |
 | 6.11   | Tree-CSP-Solver                   | `tree_csp_solver`             | [`csp.py`][csp]                 | Done | Included |
@@ -118,7 +118,7 @@ Here is a table of algorithms, the figure, name of the algorithm in the book and
 | 11.8   | Angelic-Search                    |                               |                                 |      |          |
 | 11.10  | Doubles-tennis                    | `double_tennis_problem`       | [`planning.py`][planning]       | Done | Included |
 | 13     | Discrete Probability Distribution | `ProbDist`                    | [`probability.py`][probability] | Done | Included |
-| 13.1   | DT-Agent                          | `DTAgent`                     | [`probability.py`][probability] |      |          |
+| 13.1   | DT-Agent                          | `DTAgent`                     | [`probability.py`][probability] | Done | Included |
 | 14.9   | Enumeration-Ask                   | `enumeration_ask`             | [`probability.py`][probability] | Done | Included |
 | 14.11  | Elimination-Ask                   | `elimination_ask`             | [`probability.py`][probability] | Done | Included |
 | 14.13  | Prior-Sample                      | `prior_sample`                | [`probability.py`][probability] | Done | Included |
@@ -133,7 +133,7 @@ Here is a table of algorithms, the figure, name of the algorithm in the book and
 | 17.7   | Policy-Iteration                  | `policy_iteration`            | [`mdp.py`][mdp]                 | Done | Included |
 | 17.9   | POMDP-Value-Iteration             | `pomdp_value_iteration`       | [`mdp.py`][mdp]                 | Done | Included |
 | 18.5   | Decision-Tree-Learning            | `DecisionTreeLearner`         | [`learning.py`][learning]       | Done | Included |
-| 18.8   | Cross-Validation                  | `cross_validation`            | [`learning.py`][learning]       |      |          |
+| 18.8   | Cross-Validation                  | `cross_validation`            | [`learning.py`][learning]\*     |      |          |
 | 18.11  | Decision-List-Learning            | `DecisionListLearner`         | [`learning.py`][learning]\*     |      |          |
 | 18.24  | Back-Prop-Learning                | `BackPropagationLearner`      | [`learning.py`][learning]       | Done | Included |
 | 18.34  | AdaBoost                          | `AdaBoost`                    | [`learning.py`][learning]       | Done | Included |

diff --git a/agents.py b/agents.py
@@ -131,7 +131,16 @@ def program(percept):
 
 
 def RandomAgentProgram(actions):
-    """An agent that chooses an action at random, ignoring all percepts."""
+    """An agent that chooses an action at random, ignoring all percepts.
+    >>> list = ['Right', 'Left', 'Suck', 'NoOp']
+    >>> program = RandomAgentProgram(list)
+    >>> agent = Agent(program)
+    >>> environment = TrivialVacuumEnvironment()
+    >>> environment.add_thing(agent)
+    >>> environment.run()
+    >>> environment.status == {(1, 0): 'Clean' , (0, 0): 'Clean'}
+    True
+    """
     return lambda percept: random.choice(actions)
 
 # ______________________________________________________________________________
@@ -171,7 +180,14 @@ def rule_match(state, rules):
 
 
 def RandomVacuumAgent():
-    """Randomly choose one of the actions from the vacuum environment."""
+    """Randomly choose one of the actions from the vacuum environment.
+    >>> agent = RandomVacuumAgent()
+    >>> environment = TrivialVacuumEnvironment()
+    >>> environment.add_thing(agent)
+    >>> environment.run()
+    >>> environment.status == {(1,0):'Clean' , (0,0) : 'Clean'}
+    True
+    """
     return Agent(RandomAgentProgram(['Right', 'Left', 'Suck', 'NoOp']))
 
 
@@ -192,7 +208,14 @@ def TableDrivenVacuumAgent():
 
 
 def ReflexVacuumAgent():
-    """A reflex agent for the two-state vacuum environment. [Figure 2.8]"""
+    """A reflex agent for the two-state vacuum environment. [Figure 2.8]
+    >>> agent = ReflexVacuumAgent()
+    >>> environment = TrivialVacuumEnvironment()
+    >>> environment.add_thing(agent)
+    >>> environment.run()
+    >>> environment.status == {(1,0):'Clean' , (0,0) : 'Clean'}
+    True
+    """
     def program(percept):
         location, status = percept
         if status == 'Dirty':
@@ -205,7 +228,14 @@ def program(percept):
 
 
 def ModelBasedVacuumAgent():
-    """An agent that keeps track of what locations are clean or dirty."""
+    """An agent that keeps track of what locations are clean or dirty.
+    >>> agent = ModelBasedVacuumAgent()
+    >>> environment = TrivialVacuumEnvironment()
+    >>> environment.add_thing(agent)
+    >>> environment.run()
+    >>> environment.status == {(1,0):'Clean' , (0,0) : 'Clean'}
+    True
+    """
     model = {loc_A: None, loc_B: None}
 
     def program(percept):
@@ -342,6 +372,22 @@ def __init__(self, direction):
         self.direction = direction
 
     def __add__(self, heading):
+        """
+        >>> d = Direction('right')
+        >>> l1 = d.__add__(Direction.L)
+        >>> l2 = d.__add__(Direction.R)
+        >>> l1.direction
+        'up'
+        >>> l2.direction
+        'down'
+        >>> d = Direction('down')
+        >>> l1 = d.__add__('right')
+        >>> l2 = d.__add__('left')
+        >>> l1.direction == Direction.L
+        True
+        >>> l2.direction == Direction.R
+        True
+        """
         if self.direction == self.R:
             return{
                 self.R: Direction(self.D),
@@ -364,6 +410,16 @@ def __add__(self, heading):
             }.get(heading, None)
 
     def move_forward(self, from_location):
+        """
+        >>> d = Direction('up')
+        >>> l1 = d.move_forward((0, 0))
+        >>> l1
+        (0, -1)
+        >>> d = Direction(Direction.R)
+        >>> l1 = d.move_forward((0, 0))
+        >>> l1
+        (1, 0)
+        """
         x, y = from_location
         if self.direction == self.R:
             return (x + 1, y)
@@ -940,14 +996,30 @@ def compare_agents(EnvFactory, AgentFactories, n=10, steps=1000):
     """See how well each of several agents do in n instances of an environment.
     Pass in a factory (constructor) for environments, and several for agents.
     Create n instances of the environment, and run each agent in copies of
-    each one for steps. Return a list of (agent, average-score) tuples."""
+    each one for steps. Return a list of (agent, average-score) tuples.
+    >>> environment = TrivialVacuumEnvironment
+    >>> agents = [ModelBasedVacuumAgent, ReflexVacuumAgent]
+    >>> result = compare_agents(environment, agents)
+    >>> performance_ModelBasedVacummAgent = result[0][1]
+    >>> performance_ReflexVacummAgent = result[1][1]
+    >>> performance_ReflexVacummAgent <= performance_ModelBasedVacummAgent
+    True
+    """
     envs = [EnvFactory() for i in range(n)]
     return [(A, test_agent(A, steps, copy.deepcopy(envs)))
             for A in AgentFactories]
 
 
 def test_agent(AgentFactory, steps, envs):
-    """Return the mean score of running an agent in each of the envs, for steps"""
+    """Return the mean score of running an agent in each of the envs, for steps
+    >>> def constant_prog(percept):
+    ...     return percept
+    ...
+    >>> agent = Agent(constant_prog)
+    >>> result = agent.program(5)
+    >>> result == 5
+    True
+    """
     def score(env):
         agent = AgentFactory()
         env.add_thing(agent)